J Phys Chem A [JOURNAL]
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200 papers
Cooperative Effects in the Inverse Coordination Complexes of Aromatic Azines and Tin(IV) Halides.
Matczak P
J Phys Chem A · 2026 Jul · PMID 42402215 · Publisher ↗
In this work, a series of model inverse coordination complexes composed of one aromatic azine molecule (pyrimidine, pyrazine, 1,2,4-triazine, 1,3,5-triazine, and 1,2,4,5-tetrazine) and two SnX (X = F, Cl, Br, I) molecule...
In this work, a series of model inverse coordination complexes composed of one aromatic azine molecule (pyrimidine, pyrazine, 1,2,4-triazine, 1,3,5-triazine, and 1,2,4,5-tetrazine) and two SnX (X = F, Cl, Br, I) molecules has been investigated using quantum chemical calculations. These 1:2 complexes demonstrate a rare structural motif─as evidenced by the Cambridge Structural Database (CSD)─in which a single "naked" azine center forms two N→Sn coordinate bonds simultaneously. Calculations reveal that the two bonds influence one another and, consequently, the 1:2 complexes exhibit longer N→Sn bonds and weaker interactions between the azine and SnX fragments than the corresponding 1:1 conventional complexes. Thus, the studied inverse coordination complexes are characterized by negative cooperative effects (or anticooperativity) between their N→Sn bonds. This conclusion is supported by an occurrence of the destabilizing three-body nonadditive contribution to the total interaction energy calculated at the CCSD(T)/CBS level of theory. The origin of the anticooperativity has been unveiled by the analysis of electron charge distribution and the fundamental physical nature of individual many-body contributions to the total interaction energy. Overall, this work shows how cooperative effects, together with the proper choice of azine center, can modulate the strength of N→Sn bonds in tin(IV) inverse coordination complexes.
The Infrared Spectra of Neutral Dimethyl-Sulfide, -Disulfide and -Sulfoxide Biomarkers in Molecular Beams.
Kuipers M, Pille L, Schwob L … +5 more , Oostenrijk B, Galimberti DR, Waters R, Tsai SM, Ferrari P
J Phys Chem A · 2026 Jul · PMID 42402199 · Publisher ↗
The suggested detection of sulfur-based biomarkers in the atmosphere of exoplanet K2-18b has triggered intensive discussions about the use of observational data from the James Webb Space Telescope (JWST) to search for li...
The suggested detection of sulfur-based biomarkers in the atmosphere of exoplanet K2-18b has triggered intensive discussions about the use of observational data from the James Webb Space Telescope (JWST) to search for life on exoplanets. This methodology, however, requires precise infrared spectroscopic data of biomarker molecules, ideally without the influence of pressure broadening or contaminants. In this work, we use the light of the free-electron laser FELIX to record the infrared spectrum of three sulfur-based biomarkers, dimethyl sulfide (DMS), dimethyl disulfide (DMDS), and dimethyl sulfoxide (DMSO), in the isolated conditions of a molecular beam. The use of FELIX allows the sampling of a wide spectral range, spanning from 650 to 3300 cm, where JWST is most sensitive. In addition, separate spectra of the (DMS), (DMDS) and (DMSO) dimers are recorded, allowing for a clear assessment of the effect of complexation on the infrared spectra of the molecules. Density functional theory calculations and Born-Oppenheimer molecular dynamics simulations are performed to interpret the measured infrared spectra and to estimate absolute cross sections.
Photoinduced Charge-Transfer Suppresses Triplet Formation Efficiency in Thiocoumarins: Evidence from Ultrafast Spectroscopy and Theoretical Calculations.
Dutta A, Ghosh SK, Ramamurthy V … +1 more , Sen P
J Phys Chem A · 2026 Jul · PMID 42397713 · Publisher ↗
Thiocarbonyl-containing compounds are known for their distinctive photophysical properties, particularly for their rapid intersystem crossing (ISC) and high triplet yield facilitated by enhanced spin-orbit coupling (SOC)...
Thiocarbonyl-containing compounds are known for their distinctive photophysical properties, particularly for their rapid intersystem crossing (ISC) and high triplet yield facilitated by enhanced spin-orbit coupling (SOC). However, the ISC efficiency and resulting triplet yields can vary significantly depending on molecular properties. This study explores the role of intramolecular charge transfer (CT) in modulating triplet state generation in thiocoumarins. Specifically, the introduction of a diethylamino group at the 7-position of the thiocoumarin ring (Thiocoumarin 1 or TC1) induces CT character, yielding a moderate singlet oxygen generation efficiency (0.5-0.6) and solvent polarity-dependent fluorescence property. In contrast, the 7-acetoxy-substituted derivative (Acetoxy-TC) achieves remarkably high singlet oxygen yields (0.8-0.9) that are independent of the solvent environment. Time-resolved spectroscopic measurements reveal an ultrashort fluorescence lifetime and concomitant ultrafast triplet state generation in acetoxy-TC across solvents, indicating highly efficient ISC. On the other hand, TC1 having CT behavior has relatively stable singlet excited states and slower ISC dynamics, consistent with its steady-state photophysical behavior. Complementary theoretical calculations further support these observations: acetoxy-TC exhibits solvent-independent high SOC values and a small singlet-triplet energy gap, both conducive to efficient ISC. In contrast, TC1 has less favorable ISC promoting parameters. These findings underscore the importance of molecular design, specifically avoiding CT states, in achieving efficient triplet generation in thiocarbonyl systems.
Porphyrin Aggregation Revisited: From the Four-Orbital Gouterman Model to an Eight-Orbital Framework in Porphin H-Dimers.
Förster J, Cordsmeier L, Vaz da Cruz V … +1 more , Föhlisch A
J Phys Chem A · 2026 Jul · PMID 42396895 · Publisher ↗
Porphyrin aggregation fundamentally alters photophysical properties, yet the underlying electronic structure reorganization remains poorly understood. Porphin H-type dimerization induces a characteristic blueshift of the...
Porphyrin aggregation fundamentally alters photophysical properties, yet the underlying electronic structure reorganization remains poorly understood. Porphin H-type dimerization induces a characteristic blueshift of the B-band, explained within Kasha's exciton model through dipole-dipole interactions, but this phenomenological picture does not resolve the frontier-orbital reorganization driving these changes. UV-vis spectroscopy and time-dependent density functional theory show spectral changes originate from systematic frontier-orbital splitting. The Gouterman four-orbital model extends to an eight-orbital framework in dimers through symmetric and antisymmetric combinations of the monomer HOMO-1, HOMO, LUMO, and LUMO+1. Configuration interaction within this expanded manifold governs B-band splitting, while natural transition orbital analysis shows Q-band excitations remain largely localized to single macrocycles. Nitrogen K-edge TDDFT reveals nearly unchanged core-level NEXAFS, confirming preserved local electronic structure despite valence reorganization. Aggregation thus extends Kasha's exciton picture and the Gouterman model, providing an orbital-resolved foundation for excitonic effects in porphyrin assemblies.
Unraveling the Electronic Origin of Selectivity in Ambimodal Transition States with Valence Bond Theory.
Zhang C, Wu W, Zhou C
J Phys Chem A · 2026 Jul · PMID 42396634 · Publisher ↗
Ambimodal reactions are characterized by a single transition structure that bifurcates toward multiple products, posing a fundamental challenge for understanding the origin of product selectivity. While selectivity emerg...
Ambimodal reactions are characterized by a single transition structure that bifurcates toward multiple products, posing a fundamental challenge for understanding the origin of product selectivity. While selectivity emerges along post-transition-state pathways, a direct and chemically intuitive connection between transition-state electronic structure and product distribution remains elusive. Here, we demonstrate that product selectivity in ambimodal reactions can be quantitatively correlated with a purely electronic-structure descriptor derived from valence bond (VB) theory. By analyzing the relative weights of VB structures associated with reaction pathways leading to competing products at the ambimodal transition state, a VB-based descriptor is defined to quantify product selectivity. Across a diverse set of ambimodal reactions, this descriptor exhibits a robust linear correlation with the logarithm of the product ratio obtained from experiment or trajectory simulations. These findings reveal that, although selectivity manifests dynamically after the transition state, the transition-state electronic structure contains an intrinsic electronic bias that correlates strongly with product selectivity and influences subsequent pathway bifurcation. The VB analysis thus provides a chemically intuitive perspective on bifurcating reaction pathways and complements existing approaches on ambimodal reactions.
Mechanism and Kinetics of the Initial Oxidative Ring-Opening of Corannulene Radicals under Combustion Conditions.
Gong M, Lu X, Huang Y … +2 more , Feng B, Zhang L
J Phys Chem A · 2026 Jul · PMID 42394229 · Publisher ↗
Black carbon emissions significantly impact air pollution and global warming, yet the oxidation mechanisms of curved polycyclic aromatic hydrocarbons (PAHs), which are more reactive than planar ones, remain poorly unders...
Black carbon emissions significantly impact air pollution and global warming, yet the oxidation mechanisms of curved polycyclic aromatic hydrocarbons (PAHs), which are more reactive than planar ones, remain poorly understood. In this study, the oxidation and initial ring-opening mechanisms of the corannulene radical (Cor·), the smallest stable curved PAH, were systematically investigated using ReaxFF molecular dynamics (MD), density functional theory (DFT) with ONIOM methods, and Master Equation System Solver (MESS). MD simulations reveal that the degradation is predominantly driven by the radical addition of O at the radical site (64% probability), forming the corannulene peroxyl radical (CorOO·). Subsequent unimolecular transformation analysis shows that oxygen atom transfer pathways are kinetically favored over hydrogen atom transfer and oxygen atom dissociation. Specifically, the R3-1 pathway, characterized by the lowest energy barrier (-7.8 kcal/mol), emerges as the primary sink for CorOO·, leading to efficient CO elimination. Rate constant calculations (500-2000 K) further confirm that cyclization-initiated fragmentation governs the initial oxidative degradation. This work provides the first detailed microscopic kinetic description of curved PAH oxidation, bridging the gap between planar PAH degradation and fullerene formation in combustion models.
High-Resolution Absorption Spectroscopy of ND between 59,000 and 93,000 cm.
Ashfold MNR, Jacovella U, Gans B … +5 more , Boyé-Péronne S, Joyeux D, de Oliveira N, Holland DMP, Pratt ST
J Phys Chem A · 2026 Jul · PMID 42391603 · Publisher ↗
Complementing our recent work on ammonia [Pratt et al., , 396, 111810], we here present new high-resolution photoabsorption spectra of deuterated ammonia, ND, spanning the region between 59,000 and 93,000 cm. This regio...
Complementing our recent work on ammonia [Pratt et al., , 396, 111810], we here present new high-resolution photoabsorption spectra of deuterated ammonia, ND, spanning the region between 59,000 and 93,000 cm. This region extends from just above the Franck-Condon envelope for the ̃ A″ ← ̃ A' transition to well above the ND ̃ A″ ionization threshold. The absolute photoabsorption cross sections were recorded at room temperature using the Fourier transform spectrometer at the Synchrotron SOLEIL with a measured spectral resolution of 0.22 cm, which is a factor of 10-100 times higher than in any previously reported broadband spectrum of ND. The spectra reveal partially resolved rotational structure in several different vibrational progressions, which allows the reassignment of some of the higher energy bands, enabling proposed assignments for the P1 and P2 progressions reported by Wu et al. [. , 127, 154311] and an expanded appraisal of the pattern of lower-lying Rydberg states of ammonia.
Twisted-Driven Photoionization of Aligned Chiral Molecules: Signatures of Circular and Helical Dichroism.
Duan J, Gong M, Cheng Y … +1 more , Zhang SB
J Phys Chem A · 2026 Jul · PMID 42391244 · Publisher ↗
The study of twisted light interacting with chiral molecules offers a major opportunity and challenge for probing molecular handedness using structured light fields. Through a detailed theoretical investigation of twiste...
The study of twisted light interacting with chiral molecules offers a major opportunity and challenge for probing molecular handedness using structured light fields. Through a detailed theoretical investigation of twisted-photon-induced single ionization in aligned chiral methyloxirane molecules, we consider two distinct scenarios: in ensembles of aligned molecules randomly distributed across the transverse beam profile, photon-energy and angle-resolved spectra show clear circular dichroism but no sensitivity to the light's total angular momentum (TAM), indicating that this dichroic signal reflects the combined effects of molecular chirality and molecular alignment; whereas for a single molecule or mesoscopic target at a fixed impact parameter, ionization cross sections gain sensitivity to both TAM and molecular chirality, revealing helical dichroism for forward-emitted photoelectrons and showing that spatially localized interactions allow explicit coupling between the full angular momentum of the photon and molecular chirality, thereby harnessing the spatial structure of light for chiral sensing.
Modeling the Clustering of Fumaric/Maleic Acid with Water and Na, Cl Ions.
Trolle GB, Elm J
J Phys Chem A · 2026 Jul · PMID 42390323 · Publisher ↗
Organic dicarboxylic acids are common atmospheric compounds and are important constituents of secondary organic aerosols (SOA) with implications for air quality and climate. Both fumaric acid (FA) and maleic acid (MA) ar...
Organic dicarboxylic acids are common atmospheric compounds and are important constituents of secondary organic aerosols (SOA) with implications for air quality and climate. Both fumaric acid (FA) and maleic acid (MA) are found in substantial amounts in aerosol particles and have widespread applications throughout industry. While there have been extensive studies of the isomerization and spectroscopic properties of FA and MA in aqueous solution, there has, to the best of our knowledge, not been any studies of the thermodynamic and spectroscopic properties of microhydrated gas-phase and solvated clusters of FA and MA together with Na and Cl ions. Here, we present a study of the gas-phase and aqueous-phase clusters of FA and MA together with ions by probing cluster geometries, binding and solvation free energies, and infrared (IR) absorption spectra using quantum chemical methods. We performed a detailed configurational sampling protocol to obtain gas-phase structures calculated at the DLPNO-CCSD(T)/aug-cc-pVTZ//ωB97X-D/6-31++G(d,p) level followed by a reoptimization in implicit solvent to obtain aqueous-phase structures. We find that only negligible shifts in geometry occur upon solvation of the gas-phase clusters containing FA and MA, while slightly larger rearrangements of the structures occur when solvating the ion-containing clusters. The binding free energies reveal that it is thermodynamically unfavorable to hydrate FA and MA in the gas phase but favorable to hydrate their conjugate bases (FA, MA, FA, and MA), while it is favorable to solvate all of the clusters. Furthermore, we find that it is both favorable to hydrate the ion-containing clusters in the gas phase and solvate them. Finally, in order to identify weakly bound clusters and guide future experimental work, our IR absorption analysis reveals that the harmonic frequencies of the FA and MA carboxylic O-H stretching modes of the microhydrated FA and MA clusters are red-shifted in the spectrum upon solvation. On the other hand, we find no clear trend in the spectra of the (FA)(Na)(Cl)(w) and (MA)(Na)(Cl)(w) systems, but interestingly we find consistent red-shifts in the spectra for (FA)(Na)(w), (MA)(Na)(w), (FA)(Na)(Cl)(w), and (MA)(Na)(Cl)(w).
Determining Binding Energies of Key Fluorinated Refrigerants 1,1,1,2-Tetrafluoroethane, 2,3,3,3-Tetrafluoropropene, and 3,3,3-Trifluoropropene.
Mondal K, McAnally M, Melbourne N … +4 more , Turner AM, Bergantini A, Sun R, Kaiser RI
J Phys Chem A · 2026 Jul · PMID 42389923 · Publisher ↗
Ice surfaces in the upper troposphere and polar regions act as chemically active interfaces that regulate the uptake and fate of trace gases; however, the interactions of fluorinated refrigerants with amorphous solid wat...
Ice surfaces in the upper troposphere and polar regions act as chemically active interfaces that regulate the uptake and fate of trace gases; however, the interactions of fluorinated refrigerants with amorphous solid water (ASW) have remained poorly constrained. Here, we combine temperature-programmed desorption (TPD), infrared (IR) spectroscopy, and density functional theory (DFT) to investigate the adsorption of 1,1,1,2-tetrafluoroethane (HFC-134a; CFCHF), 2,3,3,3-tetrafluoropropene (R1234yf; CFCF═CH), and 3,3,3-trifluoropropene (R1243zf; CFCH═CH) on porous ASW. TPD profiles reveal a pronounced shift in the primary desorption feature from 95-105 K (pure films) to 140-152 K on ASW, indicating enhanced binding. Desorption energies are (51 ± 4), (48 ± 3), and (45 ± 6) kJ mol, respectively, with an additional codesorption feature at 155-170 K evidencing partial trapping within the ice matrix. IR spectra exhibit red shifts of 11-21 cm in the 1000-1500 cm C-F stretching region, consistent with hydrogen bonding with the surface water network and long-range dipole interaction. DFT calculations reproduce these shifts and identify adsorption geometries governed by fluorine-OH interactions. These results demonstrate that fluorinated refrigerants can be transiently sequestered on ice, with implications for their atmospheric transport and reactivity.
Kinetic and Mechanistic Insights into H-Abstraction and Subsequent Isomerization and Decomposition of Monoglyme and Key Combustion Intermediates.
Wang C, Yan T, Zhang J … +2 more , Wang P, Zhang L
J Phys Chem A · 2026 Jul · PMID 42384400 · Publisher ↗
To provide kinetic data for a key radical-induced subnetwork in the oxidation of oxygenated polyether fuels, the potential energy surfaces for H, CH, OH, and HO-mediated H-abstraction from monoglyme (MON, CHOCHCHOCH), to...
To provide kinetic data for a key radical-induced subnetwork in the oxidation of oxygenated polyether fuels, the potential energy surfaces for H, CH, OH, and HO-mediated H-abstraction from monoglyme (MON, CHOCHCHOCH), together with the subsequent isomerization and β-scission decomposition reactions of the resulting fuel radicals, were constructed at the CCSD(T)/CBS//M06-2/6-311++G (d, p) level. High-pressure-limit and pressure-dependent rate constants were predicted using master-equation calculations over 300-2000 K. The calculated H-abstraction barriers for MON range from -1.6 to 18.5 kcal mol, corresponding to the reactivity order of OH > H > CH > HO. The site-dependent barriers are consistent with the calculated C-H bond dissociation energies (BDEs) and the stabilization of the resulting radicals. The subsequent isomerization is competitive at low temperatures. With increasing temperature, the C-O bond cleavage pathways become kinetically favored within the investigated post-H-abstraction unimolecular subnetwork, particularly the channel leading to methoxy acetaldehyde (CHOCHCHO). The H-abstraction of methoxy acetaldehyde by the four radicals mentioned above and the subsequent reactions were further investigated using the same methodology. The results indicate that the reactivity sequence of H-abstraction in methoxy acetaldehyde is consistent with that of MON. The methoxy acetaldehyde-derived radicals preferentially evolve through lower-barrier decomposition pathways rather than extensive isomerization. Comparisons with related ether systems and uncertainty analyses support the reliability of the calculated rate constants within the expected theoretical uncertainty. Implementation of the updated H-abstraction kinetics into a detailed MON oxidation mechanism affects the predicted ignition delay times. These results characterize the H-abstraction and subsequent unimolecular-reaction subnetwork from MON to methoxy acetaldehyde and smaller products, providing mechanism kinetic data for future refinement of oxygenated polyether combustion models.
First-Principles Analysis of Protonation-Induced Electronic Effects in Tetrakis(-aminophenyl)porphyrin (TAPP).
Roy A, Elmanova A, Jayan S … +4 more , Hupfer ML, Martínez TJ, Gryko DT, Presselt M
J Phys Chem A · 2026 Jul · PMID 42384378 · Publisher ↗
The optical response of pH-sensitive porphyrins depends critically on the protonation site, not merely on the total charge accumulated. Using first-principles linear-response theory, we systematically map all symmetry-di...
The optical response of pH-sensitive porphyrins depends critically on the protonation site, not merely on the total charge accumulated. Using first-principles linear-response theory, we systematically map all symmetry-distinct protonation states of tetrakis(-aminophenyl)porphyrin (TAPP), from neutral to fully protonated (+6), revealing that peripheral and core protonation produce fundamentally different photophysical outcomes. Peripheral protonation progressively attenuates Q-band intensity while leaving the macrocyclic core electronically intact, whereas core protonation drives conformer convergence, pronounced Q-band red-shifting, intensification, and merging of split-transition upon diprotonation. Q-band oscillator strength thus evolves nonmonotonically across protonation topologies─enhanced by core protonation through orbital mixing and suppressed by peripheral protonation through donor decoupling. At intermediate mixed protonation states (+4/+5), remaining unprotonated aminophenyl groups act as donors in aminophenyl-to-macrocycle charge transfer (CT) excitations, identified through charge-density difference (CDD) analysis. Core protonation additionally widens the singlet-triplet gap (Δ) relative to peripheral protonation, with implications for intersystem crossing (ISC) and triplet-state engineering. Together, these results establish protonation topology as a molecular design parameter for controlling absorption, CT character, and excited-state properties in pH-responsive porphyrin systems.
Exploring the Reactivity of the CH Radical toward Nitrous Oxide in the Context of the Interstellar Medium.
Lucas DI, Robertson ME, Scott JR … +4 more , Wu LY, Guillaume T, Heard DE, Lehman JH
J Phys Chem A · 2026 Jul · PMID 42384374 · Publisher ↗
Experimental measurements of the kinetics of the CH + NO reaction are reported for the first time for the temperature range of 32(3) - 110(4) K using the recently commissioned highly instrumented low temperature reaction...
Experimental measurements of the kinetics of the CH + NO reaction are reported for the first time for the temperature range of 32(3) - 110(4) K using the recently commissioned highly instrumented low temperature reaction chamber (HILTRAC). Furthermore, we report the characterization of a new Laval nozzle to achieve uniform supersonic flow (USF) temperatures of 73(3), 86(4), and 110(4) K with an argon buffer gas. CH radicals generated from photolysis of CHBr at 248 nm were detected by laser-induced fluorescence using the CH B Σ ← X Π (1,0) Q(1) transition near 364 nm, measuring the pseudo-first-order rate coefficients in the presence of NO. From these experiments, the reaction rate coefficient at 32(3) K was measured to be 1.7(1) × 10 cm molecule s and is at least a factor of 2 greater than the previously measured value at room temperature. The reaction rate coefficient was found to exhibit a positive temperature-dependence below 50 K, while exhibiting a negative temperature-dependence at higher temperatures. We also report the reaction potential energy surface for this reaction, performing calculations at the CCSD(T)/aug-cc-pV(Q+d)Z//M06-2X-D3/aug-cc-pV(Q+d)Z level of theory. From this, we identified reaction pathways leading to exothermic product channels for NO + HCN, NO + HNC, N + HCO, and N + H + CO, suggesting that NO + HCN are the primary reaction products due to the barrierless nature of this reaction pathway. Finally, a modified Arrhenius fit to all experimental data (32-1300 K) yields () = (9.3(4) × 10) × (/300) exp(-52(5)/) cm molecule s, which can be incorporated into astrochemical models to better understand the nitrogen-based chemistry of the interstellar medium.
Infrared Photodissociation Spectroscopy of Benzene-V(CO) "Piano Stool" Cations.
Reed ZD, Desouza MK, Odonkor RB … +1 more , Duncan MA
J Phys Chem A · 2026 Jul · PMID 42384013 · Publisher ↗
Benzene-vanadium-carbonyl cations of the form bz-V(CO) are produced in a pulsed nozzle laser vaporization source and studied by infrared photodissociation spectroscopy and density functional theory. Photofragmentation pa...
Benzene-vanadium-carbonyl cations of the form bz-V(CO) are produced in a pulsed nozzle laser vaporization source and studied by infrared photodissociation spectroscopy and density functional theory. Photofragmentation patterns indicate a stable tricarbonyl core ion. However, infrared spectroscopy and comparison to the predictions of density functional theory computations indicate that the coordination behavior is more nuanced. The small clusters contain a 16-electron tricarbonyl core ion, consistent with the fragmentation patterns. However, larger clusters with more CO ligands begin to form the tetracarbonyl ion with 18 valence electrons. The tricarbonyl and tetracarbonyl species have distinctly different infrared spectra. The asymmetric carbonyl stretch for both complexes is red-shifted from that of gas phase vanadium carbonyl, but the red shift is greater for the tetracarbonyl species.
Correction to "Solvent-Dependent Ultrafast Photochemical Dynamics of -Methyl Oxindole Overcrowded Alkene Molecular Motors".
Harris CJ, Collins BSL, Orr-Ewing AJ
J Phys Chem A · 2026 Jun · PMID 42381203 · Publisher ↗
Abstract loading — click title to view on PubMed.
Accelerating the Discovery of Superhalogens via Physics-Informed Graph Neural Networks.
Zhou D, Wang Z
J Phys Chem A · 2026 Jun · PMID 42378490 · Publisher ↗
Superhalogens are clusters with electron affinities (EAs) exceeding those of halogen atoms and are promising for applications in energy, catalysis, and electronics. However, their discovery remains difficult due to the e...
Superhalogens are clusters with electron affinities (EAs) exceeding those of halogen atoms and are promising for applications in energy, catalysis, and electronics. However, their discovery remains difficult due to the enormous number of possible compositions. Rapid, quantitatively reliable prediction of cluster electron affinity (EA) is therefore essential. This work proposed an Electron Affinity Graph Fusion Network (EAGFN) that combines local graph-convolutional embeddings of SOAP-augmented atomic features with a global many-body tensor representation (MBTR) within a lightweight residual architecture. Trained on the Cluster-AEA-2813 data set compiled from databases, EAGFN achieves a mean absolute error of 0.36 eV on the test set, outperforming conventional Graph Neural Networks (GNNs). An ensemble of five independently trained EAGFN models was then used to prioritize 1.5 × 10 hypothetical cluster formulas, yielding over 2 × 10 putative candidates with ensemble-mean EA values above the superhalogen threshold. Subsequent DFT validation of representative metal-ligand clusters, including MMX-type systems, supported their high EAs, while ligand-substitution analysis provided a qualitative explanation for the role of fluorine ligands in enhancing electron-accepting ability.
Ozonolysis of β-Caryophyllene in the Presence of Nanoscale Inhomogeneity: A Mass Spectrometry and Dynamic Light Scattering Study.
Hu M, Numadate N, Enami S
J Phys Chem A · 2026 Jun · PMID 42378368 · Publisher ↗
Water in nature is rarely present as a 100% HO but as a mixture with organic compounds, a fact that is often overlooked in laboratory studies. Here, a time-resolved mass spectrometric analysis revealed that the rates of...
Water in nature is rarely present as a 100% HO but as a mixture with organic compounds, a fact that is often overlooked in laboratory studies. Here, a time-resolved mass spectrometric analysis revealed that the rates of hydrolysis of C α-hydroxyalkyl-hydroperoxides (α-HHs) derived from the ozonolysis of β-caryophyllene, a representative atmospheric sesquiterpene, varied as a nonlinear function of water content in solutions of water:-butanol (W:TBA). The lifetimes (τ) of C α-HHs at 30, 40, 50, 60, and 70 vol % W were 407 (±98), 260 (±128), 177 (±29), 57 (±22), and 27 (±4) min, respectively. A clear kinetic threshold was observed between 50 and 60 vol % W (molar fraction χ = 0.84-0.89). In W:TBA solutions below 50 vol % W, the rates of hydrolysis of C α-HHs were remarkably slow. Dynamic light-scattering experiments indicated the presence of two sizes of droplets ( = 0.8-3.0 nm and 100-400 nm) in these visually transparent aqueous mixtures. We observed a decrease of the relative contribution to scattering intensity of nanodroplets (0.8-3.0 nm) and, in contrast, an increase of the contribution of mesoscale droplets (100-400 nm) as the water content increased from 45 to 70 vol % water (χ = 0.81-0.92). These results correlated with the hydrolysis kinetics and were consistent with a tentative mechanism in which the C α-HHs residing in the hydrophobic cores of the 0.8-3.0 nm nanodroplets did not undergo hydrolysis because of their isolation from the bulk water. We infer that similar nonlinear effects on water-related reactions would generally be operative in aqueous organic mixtures, including aqueous atmospheric aerosols.
Photodissociation Dynamics of the Zn(Acetylene) and Zn(Ethylene) Cation-π Complexes.
Blais JRC, Rittgers BM, Duncan MA
J Phys Chem A · 2026 Jun · PMID 42378107 · Publisher ↗
Zn(acetylene) and Zn(ethylene) ion-molecule complexes are investigated in the gas phase with selected-ion photofragment imaging. UV photodissociation produces respectively Zn and CH or Zn and CH fragment channels, reveal...
Zn(acetylene) and Zn(ethylene) ion-molecule complexes are investigated in the gas phase with selected-ion photofragment imaging. UV photodissociation produces respectively Zn and CH or Zn and CH fragment channels, revealing both simple bond cleavage and charge-transfer dissociation in these complexes. Imaging of each fragment channel reveals considerable kinetic energy release (KER), which provides upper limits on the bond dissociation energies (BDEs): ≤ 1.04 ± 0.20 eV (24.0 ± 4.6 kcal/mol) for Zn-(CH) and ≤ 0.82 ± 0.18 eV (18.9 ± 4.2 kcal/mol) for Zn-(CH). Agreement with previous data from spectroscopic measurements on Zn(CH) suggest that these upper limits are near the true BDE for each of these complexes. Density functional theory (DFT) calculations explore the bonding and structures of the Zn(CH) and Zn(CH) ions, employing the B3LYP, M06, M06-L, and MN15-L functionals. Time-dependent DFT (TD-DFT) computations at the B3LYP/def2-QZVP level characterize the excited states of these complexes. Zn(CH) dissociates via absorption to the bound B excited state followed by curve crossing to the A charge-transfer excited state, whereas Zn(CH) dissociates via direct excitation of the charge-transfer state.
Kinetic Approach for Assessing Absolute Hydrogen Potential (pH) across Diverse Solvents.
Sika-Nartey AT, Guo J, Broomhead WT … +2 more , Morris RH, Chin YC
J Phys Chem A · 2026 Jun · PMID 42378060 · Publisher ↗
The catalytic reactivity of the proton (H) is often governed by its chemical potential, yet quantifying this potential across nonaqueous and mixed-solvent systems remains a fundamental challenge. Here, we present a frame...
The catalytic reactivity of the proton (H) is often governed by its chemical potential, yet quantifying this potential across nonaqueous and mixed-solvent systems remains a fundamental challenge. Here, we present a framework for assessing the absolute potential of hydrogen (pH) using the electrophilic C-D/C-H substitution of phenol-d as a kinetic probe, applicable for wide-ranging solvents with diverse properties, categorized here according to their ability to solvate and stabilize sulfuric acid (HSO) and its conjugate base (HSO) as polar HSO stabilizers, polar HSO destabilizers, midpolar solvents, bridger solvents, and nonpolar solvents. In midpolar solvents, bridger solvents, and nonpolar solvents, HSO molecules form a cluster, whereas in polar HSO destabilizer solvents, HSO anions undergo homoassociation. Despite the distinct differences in solvation properties, the electrophilic C-D/C-H substitution rate constants, measured at dilute HSO concentrations and normalized to 1 mol L, exhibit a log-linear correlation with the solvent-modulated chemical potential of H, spanning ∼20 pH units and corresponding to a 37,000,000-fold variation in the normalized rate constants at 333 K. The correlation gives estimated pH values for both the nonaqueous and aqueous systems, notably in agreement between the estimated p of HSO in methanol (1.4) versus that obtained from electrochemical measurements (1.5). This framework lays the foundation for the prediction of proton reactivity in thermal catalysis.
Scalable Quantum-Classical Hybrid Algorithm for Excited States Based on Divide-and-Conquer Unitary Coupled-Cluster Linear-Response Theory Using Dynamical Polarizability.
Yoshikawa T, Takanashi T, Nakai H
J Phys Chem A · 2026 Jun · PMID 42376969 · Publisher ↗
This work introduces a divide-and-conquer (DC) quantum linear-response framework for scalable excited-state simulations, in which excitation energies and oscillator strengths are extracted from the poles of the frequency...
This work introduces a divide-and-conquer (DC) quantum linear-response framework for scalable excited-state simulations, in which excitation energies and oscillator strengths are extracted from the poles of the frequency-dependent dynamical polarizability. This feature naturally enables a fragmentation-based formulation, while retaining the ability to describe nonlocal excitations beyond predefined localization regions. The method, termed DC-qUCCSD-LR, builds upon the established self-consistent quantum linear-response (qLR) theory combined with the variational unitary coupled-cluster ansatz with single and double excitations. For linear hydrogen chains, H, the DC-qUCCSD-LR method reproduces full configuration interaction (FCI) excitation energies while significantly reducing quantum resource requirements, achieving favorable scaling of () for gate counts and () for measurements with respect to the molecular size, . These results demonstrate that the polarizability-based qUCC-LR framework and its DC extension provide an accurate and scalable foundation for quantum excited-state simulations.
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