Pub Date : 2023-11-08DOI: 10.1007/s00214-023-03063-z
Kevin Issler, Roland Mitric, Jens Petersen
Abstract In this study, we investigate the autodetachment dynamics of the 1-nitropropane anion after vibrational excitation of the energetically lowest C–H stretching mode using our recently developed extended quantum classical surface hopping approach including the detachment continuum. Therein the detachment from an electronic bound anion state is treated as a nonadiabatic transition into discretized detachment continuum states for an ensemble of classical nuclear trajectories propagated on quantum mechanical potential energy surfaces. The initial ensemble is obtained by sampling a phase space distribution accounting for the vibrational excitation of the C–H stretching mode of the molecule to match the experimental conditions. The simulated kinetic energy distribution of the ejected electrons reproduces characteristic features of the available experimental data. Analysis of the nuclear dynamics points out that the approach to neutral-like geometries with decreased pyramidalization angle of the NO $$_2$$ 2 group and reduced the N–O bond lengths are the crucial factors enhancing the ultrafast autodetachment process in vibrationally excited 1-nitropropane. This is facilitated when the dipole-bound first excited state of the anion is populated, which is structurally similar to the neutral system. Although only a small transient population of this state is observed, it acts as an efficient doorway to the detachment continuum and is responsible for a significant amount of the ejected electrons.
{"title":"A trajectory surface hopping study of the vibration-induced autodetachment dynamics of the 1-nitropropane anion","authors":"Kevin Issler, Roland Mitric, Jens Petersen","doi":"10.1007/s00214-023-03063-z","DOIUrl":"https://doi.org/10.1007/s00214-023-03063-z","url":null,"abstract":"Abstract In this study, we investigate the autodetachment dynamics of the 1-nitropropane anion after vibrational excitation of the energetically lowest C–H stretching mode using our recently developed extended quantum classical surface hopping approach including the detachment continuum. Therein the detachment from an electronic bound anion state is treated as a nonadiabatic transition into discretized detachment continuum states for an ensemble of classical nuclear trajectories propagated on quantum mechanical potential energy surfaces. The initial ensemble is obtained by sampling a phase space distribution accounting for the vibrational excitation of the C–H stretching mode of the molecule to match the experimental conditions. The simulated kinetic energy distribution of the ejected electrons reproduces characteristic features of the available experimental data. Analysis of the nuclear dynamics points out that the approach to neutral-like geometries with decreased pyramidalization angle of the NO $$_2$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mrow /> <mml:mn>2</mml:mn> </mml:msub> </mml:math> group and reduced the N–O bond lengths are the crucial factors enhancing the ultrafast autodetachment process in vibrationally excited 1-nitropropane. This is facilitated when the dipole-bound first excited state of the anion is populated, which is structurally similar to the neutral system. Although only a small transient population of this state is observed, it acts as an efficient doorway to the detachment continuum and is responsible for a significant amount of the ejected electrons.","PeriodicalId":23045,"journal":{"name":"Theoretical Chemistry Accounts","volume":"25 37","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135391695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.1007/s00214-023-03067-9
Marina Gorbunova, Sergey Shurov, Aleksandr Vasyanin, Vladimir Strelnikov
{"title":"N- and C-diallyl monomers of new structural types in radical polymerization: theoretical study on the mechanism of reaction","authors":"Marina Gorbunova, Sergey Shurov, Aleksandr Vasyanin, Vladimir Strelnikov","doi":"10.1007/s00214-023-03067-9","DOIUrl":"https://doi.org/10.1007/s00214-023-03067-9","url":null,"abstract":"","PeriodicalId":23045,"journal":{"name":"Theoretical Chemistry Accounts","volume":"48 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135411631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-26DOI: 10.1007/s00214-023-03060-2
Andrea Della Libera, Maristella Di Teodoro, Matteo Pelucchi, Carlo Cavallotti
Abstract The reactivity of aldehydes has been the subject of considerable interest in chemical kinetics, with propanal often chosen as the representative species. Despite its relevance, the reactivity of propanal is currently estimated from analogy and fitting of experimental data measured in limited temperature and pressure ranges, while the few literature theoretical studies have focused more on the exploration the potential energy surface (PES) than on the estimation of rate constants. The purpose of this work is to reinvestigate the propanal decomposition kinetics using the ab initio transition state theory based master equation approach with the intent of: (1) Determining accurate rate constants of key reaction channels; (2) Updating and validating an existing kinetic model by simulating available experimental data on propanal pyrolysis. It is found that propanal decomposition at the initial stages of pyrolysis occurs through four unimolecular barrierless reactions to form CHO + C 2 H 5 , CH 2 CHO + CH 3 , CH 3 CHCHO + H, and CH 3 CH 2 CO + H, and a termolecular pathway leading to the formation of C 2 H 4 + CO + H 2 . High pressure rate constants were determined for each barrierless reaction channel using Variable Reaction Coordinate Transition State Theory and used to estimate phenomenological temperature and pressure dependent channel specific rate constants integrating the 1 dimensional master equation over the whole PES. The decomposition rate constants so determined are in agreement with the few available experimental data and significantly faster than previous literature estimates. The estimated kinetic parameters were finally implemented into the CRECK kinetic mechanism, leading to an improved agreement with shock tube pyrolysis data from the literature.
醛类化合物的反应性一直是化学动力学研究的热点，丙醛类化合物通常被认为是其代表性物质。尽管丙醛的反应性具有一定的相关性，但目前对丙醛反应性的估计主要是通过在有限的温度和压力范围内测量的实验数据进行类比和拟合，而少数文献的理论研究更多地集中在势能面(PES)的探索上，而不是对速率常数的估计。本工作的目的是利用从头算过渡态理论为基础的主方程方法重新研究丙烷分解动力学，目的是:(1)确定准确的关键反应通道速率常数;(2)通过模拟现有丙烷热解实验数据，对已有的动力学模型进行了更新和验证。研究发现，丙烷在热解初期通过4个单分子无障碍反应生成CHO + c2h5、ch2 CHO + ch3、ch3 CHCHO + H和ch3 ch2 CO + H，并通过一个三分子途径生成c2h4 + CO + h2。利用变反应坐标过渡态理论确定了每个无障碍反应通道的高压速率常数，并利用整个PES的一维主方程来估计与温度和压力相关的现象通道特定速率常数。这样确定的分解速率常数与少数可用的实验数据一致，并且比以前的文献估计要快得多。最后将估计的动力学参数应用到CRECK动力学机制中，从而与文献中的激波管热解数据更加吻合。
{"title":"On the decomposition mechanism of propanal: rate constants evaluation and kinetic simulations","authors":"Andrea Della Libera, Maristella Di Teodoro, Matteo Pelucchi, Carlo Cavallotti","doi":"10.1007/s00214-023-03060-2","DOIUrl":"https://doi.org/10.1007/s00214-023-03060-2","url":null,"abstract":"Abstract The reactivity of aldehydes has been the subject of considerable interest in chemical kinetics, with propanal often chosen as the representative species. Despite its relevance, the reactivity of propanal is currently estimated from analogy and fitting of experimental data measured in limited temperature and pressure ranges, while the few literature theoretical studies have focused more on the exploration the potential energy surface (PES) than on the estimation of rate constants. The purpose of this work is to reinvestigate the propanal decomposition kinetics using the ab initio transition state theory based master equation approach with the intent of: (1) Determining accurate rate constants of key reaction channels; (2) Updating and validating an existing kinetic model by simulating available experimental data on propanal pyrolysis. It is found that propanal decomposition at the initial stages of pyrolysis occurs through four unimolecular barrierless reactions to form CHO + C 2 H 5 , CH 2 CHO + CH 3 , CH 3 CHCHO + H, and CH 3 CH 2 CO + H, and a termolecular pathway leading to the formation of C 2 H 4 + CO + H 2 . High pressure rate constants were determined for each barrierless reaction channel using Variable Reaction Coordinate Transition State Theory and used to estimate phenomenological temperature and pressure dependent channel specific rate constants integrating the 1 dimensional master equation over the whole PES. The decomposition rate constants so determined are in agreement with the few available experimental data and significantly faster than previous literature estimates. The estimated kinetic parameters were finally implemented into the CRECK kinetic mechanism, leading to an improved agreement with shock tube pyrolysis data from the literature.","PeriodicalId":23045,"journal":{"name":"Theoretical Chemistry Accounts","volume":"53 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134907193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-26DOI: 10.1007/s00214-023-03057-x
Mark A. Vincent, Paul L. A. Popelier
Abstract The interacting quantum atoms (IQA) method offers a rigorous and minimal route to calculate atomic electron correlation energies from the two-particle density matrix (2PDM). The price paid is that this method is very time-consuming. However, employing CCSD and CCSD(T), we explore several approaches to speed up such calculations. We make the pivotal observation that the removal, from the true 2PDM, of both the Hartree–Fock part of the 2PDM and an approximate 2PDM (Müller) dramatically reduces the size of the quadrature grid needed to obtain accurate energies.
{"title":"IQA analysis of the two-particle density matrix: chemical insight and computational efficiency","authors":"Mark A. Vincent, Paul L. A. Popelier","doi":"10.1007/s00214-023-03057-x","DOIUrl":"https://doi.org/10.1007/s00214-023-03057-x","url":null,"abstract":"Abstract The interacting quantum atoms (IQA) method offers a rigorous and minimal route to calculate atomic electron correlation energies from the two-particle density matrix (2PDM). The price paid is that this method is very time-consuming. However, employing CCSD and CCSD(T), we explore several approaches to speed up such calculations. We make the pivotal observation that the removal, from the true 2PDM, of both the Hartree–Fock part of the 2PDM and an approximate 2PDM (Müller) dramatically reduces the size of the quadrature grid needed to obtain accurate energies.","PeriodicalId":23045,"journal":{"name":"Theoretical Chemistry Accounts","volume":"103 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134908460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-24DOI: 10.1007/s00214-023-03059-9
Sumin Park, Binh Khanh Mai, Yongho Kim
{"title":"A theoretical study for spin-dependent hydrogen abstraction by non-heme FeIVO complexes based on DFT potential energy surfaces","authors":"Sumin Park, Binh Khanh Mai, Yongho Kim","doi":"10.1007/s00214-023-03059-9","DOIUrl":"https://doi.org/10.1007/s00214-023-03059-9","url":null,"abstract":"","PeriodicalId":23045,"journal":{"name":"Theoretical Chemistry Accounts","volume":"19 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135273746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-14DOI: 10.1007/s00214-023-03055-z
P. Venkata Ramana
{"title":"Experimental spectroscopic and molecular docking investigations of the anticancer drugs aprepitant and capecitabine","authors":"P. Venkata Ramana","doi":"10.1007/s00214-023-03055-z","DOIUrl":"https://doi.org/10.1007/s00214-023-03055-z","url":null,"abstract":"","PeriodicalId":23045,"journal":{"name":"Theoretical Chemistry Accounts","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135803453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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