The Journal of Physical Chemistry A最新文献

{"title":"Microhydration of Methylated Pyrazoles and Imidazoles: Robust Vibrational Resonances in Red-Shifted Water","authors":"Finn Knüppe,&nbsp;Eaindra Lwin,&nbsp;Martin A. Suhm","doi":"10.1021/acs.jpca.6c04895","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c04895","url":null,"abstract":"<p>Mono- and dihydratesof 11 <em>N</em>-methylatedpyrazolesand imidazoles are studied as vacuum-isolated complexes at low temperatureby linear infrared spectroscopy to reveal the interplay between thehydrogen-bonded water OH stretching fundamentals and anharmonic resonancepartners. The water bending overtones, with and without additionalstretching motion of a water unit against the diazole, are identifiedas the dominant resonance partners. Methyl substitution at the ringallows to tune the water OH stretch wavenumber through these resonances.A simple nested 2 × 2 model Hamiltonian, in combination withharmonic DFT predictions, provides an effective joint descriptionof the anharmonic spectra of all 22 investigated hydrogen-bonded complexes,including resonance-induced intensity redistribution patterns. Futuremultidimensional anharmonic quantum calculations can test the extentto which the proposed empirical model is successful for the rightreasons and the extent to which it may just mimic other vibrationaleffects. Model-based blind and thus unbiased predictions for 6 experimentallyuncharacterized <em>N</em>-alkylated pyrazoles and imidazolesmay allow quantification of the predictive power of the DFT-supportedanharmonic model Hamiltonian in a future investigation.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 44","pages":"8794–8805"},"PeriodicalIF":3.0,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149330381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origin-Independent Circular Dichroism Spectra for Molecular and Hybrid Systems with Real-Time Time-Dependent Density Functional Theory","authors":"Maria J. Weseloh,&nbsp;Mikael Kuisma,&nbsp;Xi Chen,&nbsp;Patrick Rinke","doi":"10.1021/acs.jpca.6c03456","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c03456","url":null,"abstract":"<p>We present a velocity gauge implementation for real-timetime-dependentdensity functional theory (RT-TDDFT) calculations of electronic circulardichroism (ECD) spectra within the linear combination of atomic orbitalsframework of the GPAW code. In contrast to the commonly used lengthgauge, which exhibits a pronounced dependence on the origin of thecoordinate system, our velocity gauge implementation produces origin-independentECD spectra already for moderately sized basis sets. The computationalefficiency of the RT-TDDFT implementation in GPAW enables efficientECD simulations of large finite systems, making chiroptical analysesof molecular and molecule–nanoparticle assemblies exceeding1000 atoms feasible.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 44","pages":"8960–8971"},"PeriodicalIF":3.0,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149330405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detailed Quasi-Classical Dynamics of the F– + SiH3I Multi-Channel Reaction","authors":"Attila Á. Dékány,&nbsp;Balázs J. Molnár,&nbsp;Gábor Czakó","doi":"10.1021/acs.jpca.6c05884","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c05884","url":null,"abstract":"<p>We extend our previous quasi-classical trajectory studyof themulti-channel F^– + SiH₃I reaction ona full-dimensional analytical potential energy surface over the collision-energyrange of 1–80 kcal/mol. We combine reaction probabilities andintegral cross sections with initial attack-angle, scattering-angle,and product-energy distributions to characterize the major and low-probabilityreaction channels. Iodide substitution is the dominant reaction throughoutthis range, followed by proton abstraction. At low collision energies,substitution is capture dominated and strongly favors Walden inversion.At higher energies, inversion and retention cross sections becomecomparable, while forward scattering becomes more pronounced, particularlyfor inversion. Proton abstraction changes markedly with collisionenergy: forward scattering increases, and the product translational-energydistribution shifts toward higher energies, consistent with an increasingcontribution from direct stripping. In contrast, hydride substitutionand several multistep minor channels show stronger internal excitation.Taken together, these results reveal distinct collision-energy-dependentmechanisms and energy-partitioning patterns among the reaction channelsof the title system.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 44","pages":"8858–8874"},"PeriodicalIF":3.0,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149330354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical and Kinetic Study on the H-Atom Abstraction Reactions of 2-Methoxypyridine by Key Combustion Species","authors":"Yu-Tong Hou,&nbsp;Ling-Nan Wu,&nbsp;Zhen-Yu Tian","doi":"10.1021/acs.jpca.6c03953","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c03953","url":null,"abstract":"<p>Combustion kinetics of nitrogen-containing heterocycliccompoundsare important for understanding fuel-nitrogen conversion and NO_x formation. Here, 2-methoxypyridine (2-MeOPy, C₆H₇NO) was selected as an oxygen- and nitrogen-containingheteroaromatic model compound to investigate H-abstraction from themethoxy side chain by key combustion species (H, CH₃, OH,HO₂, O, NH₂, NO₂, CH₃O,and O₂). Temperature- and pressure-dependent rate coefficientswere calculated using CCSD(T)-F12a/cc-pVTZ-F12//M06-2X/6–311++G(d,p)electronic-structure calculations combined with variational transition-statetheory and RRKM/master-equation calculations within the EStokTP framework.Pyridine nitrogen lowers the methoxy C–H bond dissociationenergy from 103.38 kcal·mol^–1 in anisole to97.78 kcal·mol^–1 in 2-MeOPy, but the kineticresponse remains strongly species-dependent. The calculated rate coefficientsexhibit different responses to nitrogen substitution among the investigatedabstracting species, including temperature-dependent crossovers forH- and O-initiated abstraction. The OH channel forms a hydrogen-bondedpre-reactive complex, which is associated with low-temperature curvatureand an apparent negative fitted <em>E</em>_a. Theseresults provide species-specific kinetic parameters for the developmentof detailed combustion kinetic models for nitrogen-containing fuels.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 44","pages":"8911–8922"},"PeriodicalIF":3.0,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149330366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Charge Transfer with a Spin. II: A Framework for Diabatization Which Localizes Charge and Spin","authors":"Alok Kumar,&nbsp;Zhen Tao,&nbsp;Zuxin Jin,&nbsp;Joseph E. Subotnik,&nbsp;Tian Qiu","doi":"10.1021/acs.jpca.6c03595","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c03595","url":null,"abstract":"<p>We investigate adiabatization procedure that localizes charges(in real space) and localizes spins (in spin space) for open-shellsystems that exhibit charge transfer in the presence of spin–orbitcoupling. The procedure is applied to a two-state crossing betweenpairs of Kramers-restricted doublet states (which can also be consideredeffectively a four-state crossing). To generate the relevant diabaticstates, we employ a two-step optimization over complex-unitary rotationsthat sequentially maximizes dipole and spin moments through iterativeJacobi sweeps; the resulting update rules are effectively equivalentto those of approximate joint diagonalization applied to charge andspin. The method converges rapidly and yields smooth diabatic potentialenergy surfaces that preserve dipole and spin properties (e.g., asmoothly varying spin quantization axis) along the reaction coordinatewhile maintaining time-reversal symmetry.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 44","pages":"8938–8949"},"PeriodicalIF":3.0,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149330406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isobaric Crystallization of Aqueous Magnesium Chloride Solutions at Icy Moon Conditions","authors":"Milz L. Beaumont,&nbsp;Jinjie Li,&nbsp;Miroslava Novoveska,&nbsp;Ines E. Collings,&nbsp;Craig L. Bull,&nbsp;Christoph G. Salzmann","doi":"10.1021/acs.jpca.6c05426","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c05426","url":null,"abstract":"<p>Subsurface oceans inside icy moons are expected to containdissolvedsalts whose crystallization controls the mineralogy of their hydrospheresand potentially their surfaces. Here, we use <em>in situ</em> neutron diffraction to investigate the isobaric crystallizationof a nearly saturated MgCl₂/D₂O solution betweenambient pressure and 0.4 GPa. At ambient pressure, substantial supercoolingleads primarily to MgCl₂·12D₂O, whereasincreasing the pressure to only 0.1 GPa fundamentally changes thecrystallization pathway, yielding the recently discovered MgCl₂·10D₂O-II as the dominant hydrate throughoutthe 0.1–0.4 GPa range. The simple isobaric route enables reliablepreparation of decahydrate-II, opening the door to future studies,including spectroscopic characterization relevant to its remote detectionon icy moons. We further determine a new thermal equation of stateand reveal a curious contrast between its responses to pressure andtemperature: the most compressible crystallographic direction exhibitsthe smallest thermal expansion. These findings demonstrate the importanceof pressure for understanding salt-hydrate crystallization and icy-moonmineralogy.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 44","pages":"8899–8910"},"PeriodicalIF":3.0,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149330254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mayer’s Effective Minimal Localized Molecular Orbitals","authors":"Á. Szabados,&nbsp;P. R. Surján","doi":"10.1021/acs.jpca.6c05720","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c05720","url":null,"abstract":"<p>About30 years ago, Mayer presented a theory leading to the conceptof an effective minimal atomic basis. A set of a posteriori-defined,fragment-localized molecular orbitals (LMOs) was obtained as a byproduct.In this work, a new set of LMOs, termed Mayer’s effective minimalLMOs, is derived from this byproduct; it can be viewed as arisingfrom a compactification of atomic orbitals projected onto the occupiedspace. The procedure is fully self-contained, requiring no input beyondthat of the underlying quantum chemical calculation. The resultingLMOs are orientation invariant, computationally economical, and canbe partitioned into disjoint subsets assigned to atoms or multiatomicfragments. Mayer’s effective minimal LMOs span the occupiedspace, but their number exceeds its dimension; they therefore forma frame rather than a basis in the strict sense. The size of the setdoes not grow with the original AO basis but remains at a value prescribedby the user, a prudent choice being the minimal atomic orbital basisdimension.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 44","pages":"8987–8996"},"PeriodicalIF":3.0,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149330389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular Oxygen in Organic Luminescent Adlayers: Coupled Sorption, Diffusion, Excited-State Quenching, and Recovery","authors":"Jing Zhang,&nbsp;Zhuoxuan Li,&nbsp;Chuanyu Zhang,&nbsp;Weizhuo Gao,&nbsp;Hongcheng Xu,&nbsp;Xiaoke Lu,&nbsp;Liping Ding,&nbsp;Yu Fang,&nbsp;Xueyong Wei","doi":"10.1021/acs.jpca.6c04322","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c04322","url":null,"abstract":"<p>Organicluminescent adlayers are versatile platforms for oxygensensing. Their optical responses can be tuned through molecular structure,excited-state pathway, host environment, solid-state packing, andfilm morphology. In such adlayers, however, the film-level emissionresponse cannot be ascribed to any single parameter. External oxygenpartial pressure, local oxygen concentration, and intrinsic bimolecularquenching efficiency each contribute. Oxygen must first partitionfrom the gas phase into the adlayer and diffuse through morphology-dependentpathways. It then reaches oxygen-accessible luminescent sites andquenches short- or long-lived excited states. During recovery, itdiffuses back to the interface and desorbs. This review surveys thesecoupled processes, focusing on the physical chemistry that links external <em>p</em>_O2to the local oxygen concentration near luminescentsites. We contrast the typically modest oxygen response of short-livedprompt fluorescence with that of longer-lived and triplet-involvedemissive pathways, and examine how microheterogeneity, nonlinear Stern–Volmerbehavior, and photooxidation complicate film-level calibration. Bycoupling sorption, diffusion, excited-state quenching, and recovery,this review provides a physically grounded basis for designing andassessing reversible, reproducible, and application-specific oxygen-sensingluminescent films.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 44","pages":"8723–8731"},"PeriodicalIF":3.0,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149330410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogen-Bond Network Rearrangements Induced by Selective O–H Stretching Excitation in Neon-Embedded Monoethanolamine Monohydrate","authors":"M. Øie Bischoff,&nbsp;S. Hafizi Yazdabadi,&nbsp;D. Mihrin,&nbsp;K. Louise Feilberg,&nbsp;R. Wugt Larsen","doi":"10.1021/acs.jpca.6c06188","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c06188","url":null,"abstract":"<p>The present work experimentally demonstrates that theselectiveexcitation of the hydrogen-bonded O–H stretching fundamental(OH_<em>b</em>) of the H₂O subunit inducesa concerted hydrogen-bond network rearrangement in the monoethanolamine(MEA) monohydrate embedded in neon matrices. The initially formedglobal potential energy minimum conformation of the MEA monohydrateadopts a cyclic cooperatively hydrogen-bonded “insertion”configuration, in which the H₂O molecule simultaneouslyacts as a hydrogen-bond donor to the amino group and as an acceptorfor the hydroxy group of MEA. The detection of this energeticallyfavored “insertion″ conformation is based on unambiguousassignments of characteristic intramolecular vibrational transitionsassociated with the red-shifted O–H···O hydrogen-bondedO–H stretching motion (3507 cm^–1) and theblue-shifted NH₂ wagging motion (960 cm^–1) of MEA together with the intermolecular large-amplitude in-planelibrational (hindered overall <em>c</em>-type rotational)motion of H₂O (452 cm^–1). In addition,a strong anharmonic vibrational resonance involving the highly red-shiftedO–H···N hydrogen-bonded OH_<em>b</em> fundamental state (3262 cm^–1), the HOH bendingovertone state (3173 cm^–1) and a ternary inter-intramolecularcombination state (3348 cm^–1) involving the intermolecularstretching level is rationalized by isotopic H/D and ¹⁶O/¹⁸O substitutions and is consistent with recently recognizedanharmonic vibrational resonances in amine monohydrates. Upon selectiveinfrared irradiation enabled by complementary optical filters, theexcitation within this strongly resonance-coupled O–H stretchingvibrational triad is shown to trigger a conformational transformationinto a metastable open “addition″ configuration, whichis subsequently trapped in the neon matrix cages consistent with previousfindings [<em>J. Chem. Phys.</em>, <strong>2024</strong>, 161,154301]. The experimental observations suggest that vibrational energydeposited in the intramolecular O–H stretching coordinate isredistributed (IVR) into one or more large-amplitude intermolecularvibrational coordinates, enabling barrier crossing on the underlyingintermolecular potential energy surface prior to energy dissipationinto the neon host.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 44","pages":"8889–8898"},"PeriodicalIF":3.0,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149330331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reactions of Ta+ with Acetylene Studied with Infrared Photodissociation Spectroscopy and Theory","authors":"Jens van der Hulst,&nbsp;Richard B. Odonkor,&nbsp;Nathan J. Dynak,&nbsp;Michael A. Duncan","doi":"10.1021/acs.jpca.6c05456","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c05456","url":null,"abstract":"<p>Tantalum cation complexes with up to four acetylene moleculesareinvestigated using mass spectrometry and infrared photodissociationspectroscopy. The ion complexes are produced by laser ablation inan acetylene/argon molecular beam and analyzed using a time-of-flightmass spectrometer. After mass selection, infrared photodissociationspectra recorded in the C–H and C–C stretching regionare compared with spectra predicted by DFT for different isomers.Ions of the form Ta⁺(C₂H₂) and Ta⁺(C₂H₂)_<em>n</em>–H₂ (<em>n</em> = 2–4) are observed, revealingefficient dehydrogenation and ligand coupling from the second acetylenemolecule onward. Infrared spectroscopy enables the identificationof these ligand-coupling products, revealing unexpected dehydrogenatedmetallacycle, acetylide, and metal hydride structures for <em>n</em> = 2 and 3. The third acetylene ligand completes the metalcoordination sphere, resulting in an externally bound fourth acetyleneligand. Overall, this study demonstrates the remarkable efficiencyof tantalum in promoting acetylene dehydrogenation and ligand coupling.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 44","pages":"8828–8837"},"PeriodicalIF":3.0,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149330308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}