The Journal of Physical Chemistry A最新文献

{"title":"Looking Backward and Forward","authors":"Alec Wodtke*, ","doi":"10.1021/acs.jpca.5c0132410.1021/acs.jpca.5c01324","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c01324https://doi.org/10.1021/acs.jpca.5c01324","url":null,"abstract":"","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 13","pages":"2976–2987 2976–2987"},"PeriodicalIF":2.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143758808","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":"Solvatochromism Observed in the X-ray Absorption Spectrum of Indole Dissolved in Water.","authors":"Shota Tsuru, Masanari Nagasaka","doi":"10.1021/acs.jpca.5c00456","DOIUrl":"10.1021/acs.jpca.5c00456","url":null,"abstract":"<p><p>Current developments in X-ray absorption spectroscopy (XAS) for liquid samples in the water window demand a rigorous understanding of the interactions between molecules or solute-solvent interactions observed in the spectra. Meanwhile, a theoretical description of such effects, in addition to inner-shell excitations, remains controversial. The controversy is mainly over whether the orbitals should be optimized in the final states or whether the orbital optimizations can be expressed by dynamic electron correlation. In the present work, we measured the XAS spectra of indole in aqueous solution at the carbon and nitrogen K-edges to compare them with those measured in the gas phase. Obvious solvatochromism was observed only in the XAS spectrum measured at the nitrogen K-edge. We then interpreted the observed solvatochromism by simulating spectra with both ΔSCF, where the orbitals were optimized in the final states, and the algebraic-diagrammatic construction through second order [ADC(2)], where the molecular orbitals optimized in the ground state were used throughout. The present results indicate that covalent interactions, such as hydrogen bonds, are the dominant causes of the solvation effects observed in XAS spectra. The present simulations with ΔSCF and ADC(2), in addition to some other reports, highlight the importance of optimizing the orbitals in the final inner-shell excited states for general inner-shell calculations with predictive accuracy.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"3020-3031"},"PeriodicalIF":2.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143672871","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":"Computational Design of Molecules Having Less Overlapping HOMO and LUMO in the Same Plane.","authors":"Yong-Jin Pu","doi":"10.1021/acs.jpca.5c00539","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00539","url":null,"abstract":"<p><p>The negative energy difference between singlet and triplet excited states (Δ<i>E</i>_ST) is currently attracting significant attention; however, molecular designs remain largely confined to azaphenalene structures, as reported by Leupin and Wirz in 1980. To show negative Δ<i>E</i>_ST, a maximally separated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) arrangement is crucial to minimizing the exchange interaction in the excited state. We revisited the electronic structure of cyclazine, consisting of cyclododecahexaene ([12]annulene) and a central nitrogen atom. The 12 π-electrons of the peripheral cyclic oligoene play an important role in achieving the less overlapping HOMO and LUMO arrangement, and the bridging by the nitrogen atom inside produces the energy difference between HOMO and LUMO while maintaining a stable planar structure. Based on these insights, we designed a set of 10 molecules in which the number of π-electrons (<i>N</i>) in the peripheral cyclic oligoene is 16, 20, and 24, satisfying <i>N</i> = 4·<i>n</i> (<i>n</i> = 4, 5, 6), and a further set of 11 molecules in which <i>N</i> in the peripheral cyclic oligoene is extended to 14, 18, 22, and 26, satisfying <i>N</i> = 4·<i>n</i> + 2 (<i>n</i> = 3, 4, 5, 6). HOMO, LUMO, exchange interaction (K), and Δ<i>E</i>_ST were calculated using configuration interaction singles, TD-DFT, and equation of motion coupled-cluster singles and doubles (EOM-CCSD), with the structure optimized without any symmetry constraint. Among the molecular structures with <i>N</i> = 4·<i>n</i>, only the molecules without bond alternation exhibit less overlapping HOMO and LUMO and a small K and Δ<i>E</i>_ST. In contrast, among the molecular structures with <i>N</i> = 4·<i>n</i> + 2, none of the molecules exhibit less overlapping HOMO and LUMO arrangement. The molecules with both <i>N</i> = 4·<i>n</i> and no bond alternation show negative Δ<i>E</i>_ST in the EOM-CCSD calculation. The findings of this study will pave the way for broader molecular designs of molecules exhibiting negative Δ<i>E</i>_ST, where a less overlap of HOMO and LUMO is essential.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143778513","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":"Computational Design of Molecules Having Less Overlapping HOMO and LUMO in the Same Plane","authors":"Yong-Jin Pu*,&nbsp;","doi":"10.1021/acs.jpca.5c0053910.1021/acs.jpca.5c00539","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00539https://doi.org/10.1021/acs.jpca.5c00539","url":null,"abstract":"<p >The negative energy difference between singlet and triplet excited states (Δ<i>E</i>_ST) is currently attracting significant attention; however, molecular designs remain largely confined to azaphenalene structures, as reported by Leupin and Wirz in 1980. To show negative Δ<i>E</i>_ST, a maximally separated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) arrangement is crucial to minimizing the exchange interaction in the excited state. We revisited the electronic structure of cyclazine, consisting of cyclododecahexaene ([12]annulene) and a central nitrogen atom. The 12 π-electrons of the peripheral cyclic oligoene play an important role in achieving the less overlapping HOMO and LUMO arrangement, and the bridging by the nitrogen atom inside produces the energy difference between HOMO and LUMO while maintaining a stable planar structure. Based on these insights, we designed a set of 10 molecules in which the number of π-electrons (<i>N</i>) in the peripheral cyclic oligoene is 16, 20, and 24, satisfying <i>N</i> = 4·<i>n</i> (<i>n</i> = 4, 5, 6), and a further set of 11 molecules in which <i>N</i> in the peripheral cyclic oligoene is extended to 14, 18, 22, and 26, satisfying <i>N</i> = 4·<i>n</i> + 2 (<i>n</i> = 3, 4, 5, 6). HOMO, LUMO, exchange interaction (K), and Δ<i>E</i>_ST were calculated using configuration interaction singles, TD-DFT, and equation of motion coupled-cluster singles and doubles (EOM-CCSD), with the structure optimized without any symmetry constraint. Among the molecular structures with <i>N</i> = 4·<i>n</i>, only the molecules without bond alternation exhibit less overlapping HOMO and LUMO and a small K and Δ<i>E</i>_ST. In contrast, among the molecular structures with <i>N</i> = 4·<i>n</i> + 2, none of the molecules exhibit less overlapping HOMO and LUMO arrangement. The molecules with both <i>N</i> = 4·<i>n</i> and no bond alternation show negative Δ<i>E</i>_ST in the EOM-CCSD calculation. The findings of this study will pave the way for broader molecular designs of molecules exhibiting negative Δ<i>E</i>_ST, where a less overlap of HOMO and LUMO is essential.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 15","pages":"3466–3473 3466–3473"},"PeriodicalIF":2.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837688","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":"Correction to \"Thermochemistry of Species in Gas-Phase Thermal Oxidation of C₂ to C₈ Perfluorinated Carboxylic Acids\".","authors":"Hrishikesh Ram, Thomas P Sadej, C Claire Murphy, Tim J Mallo, Phillip R Westmoreland","doi":"10.1021/acs.jpca.5c01422","DOIUrl":"10.1021/acs.jpca.5c01422","url":null,"abstract":"","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"3176-3182"},"PeriodicalIF":2.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661777","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":"Numerical Calculations of Electric Response Properties Using the Bubbles and Cube Framework.","authors":"Eelis Solala, Wen-Hua Xu, Pauli Parkkinen, Dage Sundholm","doi":"10.1021/acs.jpca.5c00849","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00849","url":null,"abstract":"<p><p>We have developed a fully numerical method for calculating the response of the Hartree-Fock orbitals to an external electric field. The Hartree-Fock orbitals are optimized using Green's function methods by iterative numerical integration of the convolution with the Helmholtz kernel. The orbital response is obtained analogously by iterative numerical integration of the convolution with the Helmholtz kernel of the Sternheimer equation. The orbitals are expanded in atom-centered functions (bubbles), consisting of numerical radial functions multiplied by spherical harmonics. The remainder, i.e., the difference between the bubble expansion and the exact orbitals, is expanded in numerical tensorial local basis functions on a three-dimensional grid (cube). The methods have been tested by calculating polarizabilities for He, H₂, and NH₃, which are compared to the literature values.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143762601","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":"Numerical Calculations of Electric Response Properties Using the Bubbles and Cube Framework","authors":"Eelis Solala,&nbsp;Wen-Hua Xu,&nbsp;Pauli Parkkinen and Dage Sundholm*,&nbsp;","doi":"10.1021/acs.jpca.5c0084910.1021/acs.jpca.5c00849","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00849https://doi.org/10.1021/acs.jpca.5c00849","url":null,"abstract":"<p >We have developed a fully numerical method for calculating the response of the Hartree–Fock orbitals to an external electric field. The Hartree–Fock orbitals are optimized using Green’s function methods by iterative numerical integration of the convolution with the Helmholtz kernel. The orbital response is obtained analogously by iterative numerical integration of the convolution with the Helmholtz kernel of the Sternheimer equation. The orbitals are expanded in atom-centered functions (bubbles), consisting of numerical radial functions multiplied by spherical harmonics. The remainder, i.e., the difference between the bubble expansion and the exact orbitals, is expanded in numerical tensorial local basis functions on a three-dimensional grid (cube). The methods have been tested by calculating polarizabilities for He, H₂, and NH₃, which are compared to the literature values.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 14","pages":"3368–3374 3368–3374"},"PeriodicalIF":2.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.jpca.5c00849","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143806757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First-Generation Products of <i>Trans</i>-2-Hexenal Ozonolyis: A New Look at the Mechanism.","authors":"Najoua Derbel, Alexander Alijah, Struan H Robertson, Thomas Lauvaux, Lilian Joly","doi":"10.1021/acs.jpca.4c07608","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c07608","url":null,"abstract":"<p><p>The ozonolysis reaction of <i>trans</i>-2-hexenal was studied theoretically on the basis of highly accurate CCSD(T)-F12b/AVTZ energy values obtained in M06-2X/AVTZ preoptimized nuclear configurations. The kinetics was modeled with the help of the master equation solver MESMER. Apart from the expected stable oxidation products 1-butanal (17%) and glyoxal (35%), a secondary ozonide is formed on the glyoxal channel, which is the principal first-generation product (49%). It is further shown that glyoxal is created on two competing pathways, one of which leads to simultaneous production of the ester propylformate (18%). The inclusion of all of these mechanisms explains the experimental findings and identifies for the first time the origin of the experimental carbon deficit.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143762583","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":"IR Spectroscopy of 4-Aminobenzonitrile⁺-Ar_<i>n</i> (<i>n</i> = 0-2): Determination of the Activation Barrier for the π → NH Site-Switching Reaction.","authors":"Shino Yukumi, Otto Dopfer, Mitsuhiko Miyazaki","doi":"10.1021/acs.jpca.5c00730","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00730","url":null,"abstract":"<p><p>Information about the intermolecular potential energy surface for the interaction between solute and solvent molecules is required to understand the impact of solvation on reaction mechanisms and dynamics. In this study, we measured vibrational-specific infrared (IR) spectra of 4-aminobenzonitrile-(argon)_<i>n</i> cation clusters, 4ABN⁺-Ar_<i>n</i> (<i>n</i> = 1, 2), in the NH stretching range to elucidate the energetics of the photoionization-induced π → NH migration of Ar. The IR spectra of 4ABN⁺-Ar_<i>n</i> generated by resonant photoionization of neutral π-bonded clusters display the hydrogen-bonded NH₂ stretching vibration (ν_NH₂) only when intermolecular vibrational levels are excited. This is the first observation of Ar migration from the aromatic ring toward the NH₂ group upon photoionization in the <i>n</i> = 1 cluster. From the vibrational-level dependence of the IR spectra, the activation barrier heights are determined to be 21-47 (34 ± 13) and <27 cm^-1 for 4ABN⁺-Ar₁ and 4ABN⁺-Ar₂, respectively. The potential energy surfaces and mechanism of the Ar migration are discussed with the help of complementary density functional theory calculations.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770746","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":"Infrared Multiple Photon Dissociation Spectroscopy of the H–H Stretching Mode and Low-Lying Electronic Transitions in Fe+(H2)1,2 and Fe+(D2)1,2","authors":"Shan Jin,&nbsp;Marcos Juanes,&nbsp;Christian van der Linde,&nbsp;Milan Ončák* and Martin K. Beyer*,&nbsp;","doi":"10.1021/acs.jpca.5c0019610.1021/acs.jpca.5c00196","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00196https://doi.org/10.1021/acs.jpca.5c00196","url":null,"abstract":"<p >Although iron is the most abundant transition metal in the interstellar medium, its interaction with hydrogen─by far the most abundant element─in small gas-phase molecules or complexes is poorly understood. Herein, we study the infrared spectroscopy of cationic iron complexes with one and two dihydrogen ligands, Fe⁺(H₂)_1,2, as well as their deuterated counterparts, Fe⁺(D₂)_1,2, using infrared multiple photon dissociation (IRMPD) spectroscopy. Quantum chemical calculations, including multireference configuration interaction (MRCI) with spin–orbit coupling, are used to simulate the electronic and vibrational contributions to the spectra. Broad electronic transitions are observed in the studied energy range of 2230–4000 cm^–1, which arise from d–d transitions at the metal center between states of quartet spin multiplicity. In the complex, the H–H stretching mode of the H₂ ligand becomes infrared active, and features arising from this mode are assigned with the help of quantum chemical calculations in the spectra of Fe⁺(H₂) and Fe⁺(D₂)₂. In Fe⁺(H₂), we assign a band with local maxima centered at ∼3138 cm^–1 and ∼3219 cm^–1 to the P and R branches of the H–H stretching mode, while the D–D stretch of Fe⁺(D₂)₂ has a band centered at 2448 cm^–1, with P and R branches not resolved. With a D/H wavenumber ratio of 0.726, the D–D stretch of Fe⁺(D₂) and the H–H stretch of Fe⁺(H₂)₂ are expected at 2309 cm^–1 and 3372 cm^–1, respectively. The rovibrational bands in Fe⁺(H₂) and Fe⁺(D₂)₂ exhibit pronounced broadening that cannot be explained by temperature. We assign the broadening to the strong dependence of the H–H and D–D stretching frequencies on the torsional motion of the complex, as shown by the calculations. The extreme redshift of the H–H and D–D stretching frequencies is caused by back-donation from iron d_<i>xz</i>, d_<i>yz</i> atomic orbitals into the σ* orbital of the H₂ molecule, which weakens the H–H bond.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 15","pages":"3455–3465 3455–3465"},"PeriodicalIF":2.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.jpca.5c00196","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}