Briony Downes-Ward, Abbas Behzadfar, Shameemah Thawoos, Arthur Suits
{"title":"通过宽带旋转光谱检测草唑光解过程中的产物分支","authors":"Briony Downes-Ward, Abbas Behzadfar, Shameemah Thawoos, Arthur Suits","doi":"10.1039/d4cp03276d","DOIUrl":null,"url":null,"abstract":"The photodissociation of oxazole (c-C3H3NO) following excitation at 193 nm is studied using mm-Wave rotational spectroscopy in a uniform supersonic flow. Molecules entrained in the flow are excited onto a ππ* state after which it is believed most relax back onto the ground state via ring opening at the O-C[N] bond with subsequent fragmentation. From the line intensities of the probed products, we obtained the branching fractions for seven different products which are the result of five different dissociation pathways. The detected photoproducts and respective branching fractions (%) are the following: HCN (70.4), HCO (22.8), CH2CN (4.2), CH2CO (1.0), CH3CN (1.0), HNC (0.9), HNCO (0.08). We suspect much of the HCO may be formed in conjunction with the isocyanomethyl radical, CH2NC, which we did not probe. We discuss our results in relation to previous work, in particular our own study on the related isomer isoxazole, as well as direct dynamics theoretical simulations from the literature. We also studied the relaxation of a number of vibrationally excited levels of HCN produced at 20 K.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Product branching in the photodissociation of oxazole detected by broadband rotational spectroscopy\",\"authors\":\"Briony Downes-Ward, Abbas Behzadfar, Shameemah Thawoos, Arthur Suits\",\"doi\":\"10.1039/d4cp03276d\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The photodissociation of oxazole (c-C3H3NO) following excitation at 193 nm is studied using mm-Wave rotational spectroscopy in a uniform supersonic flow. Molecules entrained in the flow are excited onto a ππ* state after which it is believed most relax back onto the ground state via ring opening at the O-C[N] bond with subsequent fragmentation. From the line intensities of the probed products, we obtained the branching fractions for seven different products which are the result of five different dissociation pathways. The detected photoproducts and respective branching fractions (%) are the following: HCN (70.4), HCO (22.8), CH2CN (4.2), CH2CO (1.0), CH3CN (1.0), HNC (0.9), HNCO (0.08). We suspect much of the HCO may be formed in conjunction with the isocyanomethyl radical, CH2NC, which we did not probe. We discuss our results in relation to previous work, in particular our own study on the related isomer isoxazole, as well as direct dynamics theoretical simulations from the literature. We also studied the relaxation of a number of vibrationally excited levels of HCN produced at 20 K.\",\"PeriodicalId\":99,\"journal\":{\"name\":\"Physical Chemistry Chemical Physics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.9000,\"publicationDate\":\"2024-10-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Physical Chemistry Chemical Physics\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://doi.org/10.1039/d4cp03276d\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physical Chemistry Chemical Physics","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1039/d4cp03276d","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Product branching in the photodissociation of oxazole detected by broadband rotational spectroscopy
The photodissociation of oxazole (c-C3H3NO) following excitation at 193 nm is studied using mm-Wave rotational spectroscopy in a uniform supersonic flow. Molecules entrained in the flow are excited onto a ππ* state after which it is believed most relax back onto the ground state via ring opening at the O-C[N] bond with subsequent fragmentation. From the line intensities of the probed products, we obtained the branching fractions for seven different products which are the result of five different dissociation pathways. The detected photoproducts and respective branching fractions (%) are the following: HCN (70.4), HCO (22.8), CH2CN (4.2), CH2CO (1.0), CH3CN (1.0), HNC (0.9), HNCO (0.08). We suspect much of the HCO may be formed in conjunction with the isocyanomethyl radical, CH2NC, which we did not probe. We discuss our results in relation to previous work, in particular our own study on the related isomer isoxazole, as well as direct dynamics theoretical simulations from the literature. We also studied the relaxation of a number of vibrationally excited levels of HCN produced at 20 K.
期刊介绍:
Physical Chemistry Chemical Physics (PCCP) is an international journal co-owned by 19 physical chemistry and physics societies from around the world. This journal publishes original, cutting-edge research in physical chemistry, chemical physics and biophysical chemistry. To be suitable for publication in PCCP, articles must include significant innovation and/or insight into physical chemistry; this is the most important criterion that reviewers and Editors will judge against when evaluating submissions.
The journal has a broad scope and welcomes contributions spanning experiment, theory, computation and data science. Topical coverage includes spectroscopy, dynamics, kinetics, statistical mechanics, thermodynamics, electrochemistry, catalysis, surface science, quantum mechanics, quantum computing and machine learning. Interdisciplinary research areas such as polymers and soft matter, materials, nanoscience, energy, surfaces/interfaces, and biophysical chemistry are welcomed if they demonstrate significant innovation and/or insight into physical chemistry. Joined experimental/theoretical studies are particularly appreciated when complementary and based on up-to-date approaches.