The Journal of Physical Chemistry A最新文献

{"title":"Correction to \"Thermochemistry of Gas-Phase Thermal Oxidation of C₂ to C₈ Perfluorinated Sulfonic Acids with Extrapolation to C₁₆\".","authors":"Hrishikesh Ram, C Murphy DePompa, Phillip R Westmoreland","doi":"10.1021/acs.jpca.5c01423","DOIUrl":"10.1021/acs.jpca.5c01423","url":null,"abstract":"","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"2823-2827"},"PeriodicalIF":2.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143571565","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":"Diabatic Potential Energy Surfaces of the H₂S⁺ System and the Dynamics Studies of the S⁺ + H₂ (<i>v</i>₀ = 2, <i>j</i>₀ = 0) Reaction.","authors":"Yong Zhang, Wentao Li","doi":"10.1021/acs.jpca.5c00013","DOIUrl":"10.1021/acs.jpca.5c00013","url":null,"abstract":"<p><p>Global diabatic potential energy surfaces (PESs) of the H₂S⁺ system, corresponding to the 1⁴A″ and 2⁴A″ electronic states, were built by using the neural network method. In ab initio calculations, the aug-cc-pVTZ basis set and MRCI-F12 method were adopted. The topographic features of the new diabatic PESs were discussed and compared with the available theoretical and experimental results in detail. The spectroscopic parameters obtained from the diabatic PESs are in good agreement with previous theoretical and experimental results. Based on the newly constructed diabatic PESs, the nonadiabatic dynamics calculations of the S⁺ + H₂(<i>v</i>₀ = 2, <i>j</i>₀ = 0) → SH⁺ + H reaction were carried out using the time-dependent wave packet method. To further understand the nonadiabatic effect, the adiabatic dynamical calculations of the title reaction were also performed based on the adiabatic PES, which was obtained by diagonalizing the diabatic PESs. The deviation between nonadiabatic results and adiabatic values is very obvious. In general, the adiabatic results underestimate the dynamics result at low collision energies and overestimate the dynamics results within high collision energy ranges. Therefore, to obtain accurate dynamics results, the nonadiabatic effect should be included in the calculation.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"2780-2790"},"PeriodicalIF":2.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143582142","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":"UV Photodissociation Dynamics of Organic Hydroperoxides: Experiment and Theory","authors":"Meijun Zou,&nbsp;Emmanuel Moya Cruz,&nbsp;Christopher A. Sojdak,&nbsp;Marisa C. Kozlowski,&nbsp;Tolga N. V. Karsili and Marsha I. Lester*,&nbsp;","doi":"10.1021/acs.jpca.5c0076210.1021/acs.jpca.5c00762","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00762https://doi.org/10.1021/acs.jpca.5c00762","url":null,"abstract":"<p >The UV photodissociation dynamics of three organic hydroperoxides (ROOH, <i>R</i> = <i>tert</i>-butyl, cyclopentyl, and cyclohexyl) are examined experimentally at 282 nm utilizing velocity map imaging of the OH X²Π_3/2 (v″ = 0, J″) products. The three systems have similar O–O bond dissociation energies based on W1BD calculations and thus similar energy release to products. In each case, the experimental total kinetic energy release (TKER) distributions are bimodal, composed of narrow low and broad high TKER components extending over the available energy. The associated angular distributions of the OH X²Π products are isotropic, differing dramatically from those predicted for direct photodissociation. Complementary theoretical calculations map the relaxed potential energy profile for each ROOH along the steeply repulsive excited state (S₁) potential leading to RO + OH products. Low CCOO torsional barriers predicted along the ROOH dissociation pathway enable the OH products to recoil in many different directions, yielding isotropic angular distributions. Simple models of photodissociation suggest that the low TKER component arises from internal conversion to the ground state (S₀) potential, leading to a common RO + OH product asymptote. A simple impulsive model for dissociation captures some aspects of the high TKER component but neglects significant geometric changes in the alkyl substituent from ROOH to the RO product. This study provides new insight into the solar photolysis of organic hydroperoxides and the regeneration of OH radicals in atmospheric oxidation cycles.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 13","pages":"3052–3062 3052–3062"},"PeriodicalIF":2.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143758859","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 Properties of Hydroxyamino Acids in Water","authors":"Roman Boča*,&nbsp;Žofia Rádiková,&nbsp;Juraj Štofko,&nbsp;Beata Vranovičová and Cyril Rajnák,&nbsp;","doi":"10.1021/acs.jpca.5c0070110.1021/acs.jpca.5c00701","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00701https://doi.org/10.1021/acs.jpca.5c00701","url":null,"abstract":"<p >Aliphatic hydroxyamino acids, namely, α-hydroxyglycine, α-hydroxyalanine, serine, threonine, and homoserine, were studied by quantum chemical calculations using two methods in water as a solvent. A hybrid variant of DFT–B3LYP was applied to optimize the geometry of neutral molecules, molecular cations, and anions for the canonical and zwitterionic form of amino acids. In the energy minimum, vibrational analysis was applied, enabling the evaluation of thermodynamic functions (internal energy, enthalpy, entropy, and Gibbs energy) of individual species and absolute oxidation and reduction potentials for redox couples. In the B3LYP preoptimized geometry, the advanced DLPNO–CCSD(T) method was applied to include the major part of the interelectron correlation energy. Calculated molecular descriptors were compared with previously studied molecules by the same method, and the whole set for 17 amino acids was processed by advanced statistical methods such as cluster analysis and principal component analysis. Calculated oxidation potentials correlate with the adiabatic ionization energies along a straight line, and analogously, the calculated reduction potential correlates with the electrophilicity index. The ionization energy in α-amino acids is systematically influenced (reduced) by the functional groups such as hydroxyl, methyl, ethyl, and <i>iso</i>-propyl; it decreases along a series of α-, β-, γ-, and δ-amino acids.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 12","pages":"2903–2911 2903–2911"},"PeriodicalIF":2.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703811","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,&nbsp;Thomas P. Sadej,&nbsp;C. Claire Murphy,&nbsp;Tim J. Mallo and Phillip R. Westmoreland*,&nbsp;","doi":"10.1021/acs.jpca.5c0142210.1021/acs.jpca.5c01422","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c01422https://doi.org/10.1021/acs.jpca.5c01422","url":null,"abstract":"","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 13","pages":"3176–3182 3176–3182"},"PeriodicalIF":2.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143758813","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":"Local-Density Correlation Functional from the Force-Balance Equation.","authors":"Nicolas Tancogne-Dejean, Markus Penz, Michael Ruggenthaler, Angel Rubio","doi":"10.1021/acs.jpca.4c07235","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c07235","url":null,"abstract":"<p><p>The force-balance equation of time-dependent density-functional theory presents a promising route toward obtaining approximate functionals; however, so far, no practical correlation functionals have been derived this way. In this work, starting from a correlated wave function proposed originally by Colle and Salvetti [Theoret. Chim. Acta 37, 329 (1975)], we derive an analytical correlation-energy functional for the ground state based on the force-balance equation. The new functional is compared to the local-density correlation of the homogeneous electron gas, and we find an increased performance for atomic systems, while it performs slightly worse on solids. From this point onward, the new force-based correlation functional can be systematically improved.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661555","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":"Harnessing the (CH₃)₂ZnCl^- Anion for Dimethylzinc Stabilization as a Pathway to Stable Dimethylzinc Salts and Dimethylzinc Recovery.","authors":"Dawid Falkowski, Alicja Mikolajczyk, Piotr Skurski","doi":"10.1021/acs.jpca.5c00568","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00568","url":null,"abstract":"<p><p>The possibility of stabilizing reactive dimethylzinc through salt formation has been investigated using advanced <i>ab initio</i> electronic structure methods and flexible basis sets. It was found that the attachment of a Cl^- ion to dimethylzinc is thermodynamically favorable (with a Gibbs free reaction energy of -22.88 kcal/mol at room temperature), occurring without a kinetic barrier. The resulting anion is strongly electronically bound, with an excess electron binding energy of 4.306 eV. The subsequent attachment of Li⁺ or Na⁺ ions to this anion leads to the formation of ionic salts (CH₃)₂ZnClLi or (CH₃)₂ZnClNa. These salts, formed through this two-step process, are thermodynamically stable and represent stabilized forms of dimethylzinc, from which the pure dimethylzinc compound can be regenerated via the procedures suggested in this work. In addition to the structural characterization of these systems and a detailed analysis of the electronic structure of the (CH₃)₂ZnCl^- anion, which plays a key role in the described process, experimental approaches for realizing each transformation are also proposed.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661779","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":"Similarity-Informed Matrix Completion Method for Predicting Activity Coefficients.","authors":"Nicolas Hayer, Thomas Specht, Justus Arweiler, Hans Hasse, Fabian Jirasek","doi":"10.1021/acs.jpca.4c08360","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c08360","url":null,"abstract":"<p><p>Accurate prediction of thermodynamic properties of mixtures, such as activity coefficients, is essential for designing and optimizing chemical processes. While established physics-based methods face limitations in prediction accuracy and scope, emerging machine learning approaches, such as matrix completion methods (MCMs), offer promising alternatives. However, their performance can suffer in data-sparse regions. To address this issue, we propose a novel hybrid MCM for predicting activity coefficients at infinite dilution at 298 K that not only uses experimental training data but also includes synthetic training data from two sources: predictions obtained from the physics-based modified UNIFAC (Dortmund) and from a similarity-based approach developed in previous work. The resulting hybrid method combines the broad applicability of MCMs with the precision of the similarity-based approach, resulting in a more robust prediction framework that excels even in regions with limited data. Additionally, our analysis provides valuable insights into how different types of training data affect the prediction accuracy. When experimental data are sparse, incorporating synthetic training data from modified UNIFAC (Dortmund) and the similarity-based approach significantly improves the performance of the MCMs. Conversely, even with abundant experimental data, high accuracy is achieved only if the training set includes mixtures similar to those of interest.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655529","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":"Machine Learning Approaches for Developing Potential Surfaces: Applications to OH–(H2O)n (n = 1–3) Complexes","authors":"Greta M. Jacobson,&nbsp;Lixue Cheng*,&nbsp;Vignesh C. Bhethanabotla,&nbsp;Jiace Sun and Anne B. McCoy*,&nbsp;","doi":"10.1021/acs.jpca.4c0882610.1021/acs.jpca.4c08826","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c08826https://doi.org/10.1021/acs.jpca.4c08826","url":null,"abstract":"<p >An approach for obtaining high-level <i>ab initio</i> potential surfaces is described. The approach takes advantage of machine learning strategies in a two-step process. In the first, the molecular-orbital based machine learning (MOB-ML) model uses Gaussian process regression to learn the correlation energy at the CCSD(T) level using the molecular orbitals obtained from Hartree–Fock calculations. In this work, the MOB-ML approach is expanded to use orbitals obtained using a smaller basis set, aug-cc-pVDZ, as features for learning the correlation energies at the complete basis set (CBS) limit. This approach is combined with the development of a neural-network potential, where the sampled geometries and energies that provide the training data for the potential are obtained using a diffusion Monte Carlo (DMC) calculation, which was run using the MOB-ML model. Protocols are developed to make full use of the structures that are obtained from the DMC calculation in the training process. These approaches are used to develop potentials for OH^–(H₂O) and H₃O⁺(H₂O), which are used for subsequent DMC calculations. The results of these calculations are compared to those performed using previously reported potentials. Overall, the results of the two sets of DMC calculations are in good agreement for these very floppy molecules. Potentials are also developed for OH^–(H₂O)₂ and OH^–(H₂O)₃, for which there are not available potential surfaces. The results of DMC calculations for these ions are compared to those for the corresponding H₃O⁺(H₂O)₂ and H₃O⁺(H₂O)₃ ions. It is found that the level of delocalization of the shared proton is similar for a hydroxide or hydronium ion bound to the same number of water molecules. This finding is consistent with the experimental observation that these sets of ions have similar spectra.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 12","pages":"2958–2972 2958–2972"},"PeriodicalIF":2.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703812","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":"Similarity-Informed Matrix Completion Method for Predicting Activity Coefficients","authors":"Nicolas Hayer,&nbsp;Thomas Specht,&nbsp;Justus Arweiler,&nbsp;Hans Hasse and Fabian Jirasek*,&nbsp;","doi":"10.1021/acs.jpca.4c0836010.1021/acs.jpca.4c08360","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c08360https://doi.org/10.1021/acs.jpca.4c08360","url":null,"abstract":"<p >Accurate prediction of thermodynamic properties of mixtures, such as activity coefficients, is essential for designing and optimizing chemical processes. While established physics-based methods face limitations in prediction accuracy and scope, emerging machine learning approaches, such as matrix completion methods (MCMs), offer promising alternatives. However, their performance can suffer in data-sparse regions. To address this issue, we propose a novel hybrid MCM for predicting activity coefficients at infinite dilution at 298 K that not only uses experimental training data but also includes synthetic training data from two sources: predictions obtained from the physics-based modified UNIFAC (Dortmund) and from a similarity-based approach developed in previous work. The resulting hybrid method combines the broad applicability of MCMs with the precision of the similarity-based approach, resulting in a more robust prediction framework that excels even in regions with limited data. Additionally, our analysis provides valuable insights into how different types of training data affect the prediction accuracy. When experimental data are sparse, incorporating synthetic training data from modified UNIFAC (Dortmund) and the similarity-based approach significantly improves the performance of the MCMs. Conversely, even with abundant experimental data, high accuracy is achieved only if the training set includes mixtures similar to those of interest.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 13","pages":"3141–3147 3141–3147"},"PeriodicalIF":2.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143758846","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}