Mahesh K Sit, Subhasish Das, Prashant Kumar, Kousik Samanta
{"title":"Photodissociation pathways in the simplest Criegee intermediate: a semi-classical investigation","authors":"Mahesh K Sit, Subhasish Das, Prashant Kumar, Kousik Samanta","doi":"10.1007/s12039-023-02197-8","DOIUrl":null,"url":null,"abstract":"<div><p>The dissociation of the simplest Criegee intermediate (H<span>\\(_2\\)</span>COO) into formaldehyde (H<span>\\(_2\\)</span>CO) and oxygen atom (O) is very important in the atmospheric chemistry. In this study, we investigate the photodissociation of the O–O bond of H<span>\\(_2\\)</span>COO by simulating the dynamics of the process on the fitted multiconfigurational adiabatic potential energy surfaces (PESs). Tully’s fewest-switches surface hopping (FSSH) method is used for the simulation. The FSSH trajectories are initiated on the lowest optically-bright singlet excited state (<span>\\(S_2\\)</span>) and propagated along the O–O coordinate. Some of the trajectories end up on energetically lower PESs as a result of radiationless transfer through conical intersections. However, all the trajectories lead to O–O bond dissociation <i>via</i> one of the two channels. The simulation results demonstrate that the restricted O–O motion dissociates H<span>\\(_2\\)</span>COO into singlet fragments <i>via</i> the lower energy channel. The coupling of electronic states along O–O may account for this.</p><h3>Graphical abstract</h3><p>The photodissociation of simplest Criegee intermediate (H<sub>2</sub>COO) into formaldehyde (H<sub>2</sub>CO) and oxygen (O) was studied using Tully's fewest-switches surface hopping (FSSH). The simulation results demonstrate that the restricted O–O motion dissociates into singlet fragments <i>via</i> the lower energy channel.</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":616,"journal":{"name":"Journal of Chemical Sciences","volume":null,"pages":null},"PeriodicalIF":1.7000,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Chemical Sciences","FirstCategoryId":"92","ListUrlMain":"https://link.springer.com/article/10.1007/s12039-023-02197-8","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The dissociation of the simplest Criegee intermediate (H\(_2\)COO) into formaldehyde (H\(_2\)CO) and oxygen atom (O) is very important in the atmospheric chemistry. In this study, we investigate the photodissociation of the O–O bond of H\(_2\)COO by simulating the dynamics of the process on the fitted multiconfigurational adiabatic potential energy surfaces (PESs). Tully’s fewest-switches surface hopping (FSSH) method is used for the simulation. The FSSH trajectories are initiated on the lowest optically-bright singlet excited state (\(S_2\)) and propagated along the O–O coordinate. Some of the trajectories end up on energetically lower PESs as a result of radiationless transfer through conical intersections. However, all the trajectories lead to O–O bond dissociation via one of the two channels. The simulation results demonstrate that the restricted O–O motion dissociates H\(_2\)COO into singlet fragments via the lower energy channel. The coupling of electronic states along O–O may account for this.
Graphical abstract
The photodissociation of simplest Criegee intermediate (H2COO) into formaldehyde (H2CO) and oxygen (O) was studied using Tully's fewest-switches surface hopping (FSSH). The simulation results demonstrate that the restricted O–O motion dissociates into singlet fragments via the lower energy channel.
期刊介绍:
Journal of Chemical Sciences is a monthly journal published by the Indian Academy of Sciences. It formed part of the original Proceedings of the Indian Academy of Sciences – Part A, started by the Nobel Laureate Prof C V Raman in 1934, that was split in 1978 into three separate journals. It was renamed as Journal of Chemical Sciences in 2004. The journal publishes original research articles and rapid communications, covering all areas of chemical sciences. A significant feature of the journal is its special issues, brought out from time to time, devoted to conference symposia/proceedings in frontier areas of the subject, held not only in India but also in other countries.