{"title":"近红外激光在O2气体中产生折射率光栅:单分子和双分子吸收和碰撞弛豫的作用","authors":"Dimitrii N. Kozlov","doi":"10.1016/j.chemphys.2025.112619","DOIUrl":null,"url":null,"abstract":"<div><div>Laser-induced gratings (LIGs) were generated in neat O<sub>2</sub> at ambient temperature by photoexcitation of molecular species with nanosecond laser pulses at 1064 nm. LIGs were created at atmospheric pressure at different laser frequencies around that of the <sup><em>R</em></sup><em>R</em>(11) transition of the O<sub>2</sub>(<em>a</em> <sup>1</sup>Δ<sub><em>g</em></sub>, <em>υ</em> = 1) ← O<sub>2</sub>(<em>X</em> <sup>3</sup>Σ<sub><em>g</em></sub><sup>−</sup>, <em>υ</em> = 0) absorption band of O<sub>2</sub> monomers, and over a wide pressure range (1–130 bar) at a fixed frequency. LIGs were probed by diffracting continuous wave laser radiation.</div><div>The proposed modeling indicates that at small delays (0–2 μs) LIGs are formed, in addition to electrostriction, by “instantaneous” collisional exchange of energy between the molecular species and the environment resulting from radiation absorption by O<sub>2</sub>-O<sub>2</sub> dimols and the subsequent breakdown of the laser-excited species, with collisional emergence of electronically and vibrationally excited O<sub>2</sub> monomers. At large delays (20–1000 μs), LIGs are created by the “slow” collisional relaxation of the produced excited monomers.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"593 ","pages":"Article 112619"},"PeriodicalIF":2.0000,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Near-IR range laser generation of refractive index gratings in O2 gas: Role of mono- and bimolecular absorption and collisional relaxation\",\"authors\":\"Dimitrii N. Kozlov\",\"doi\":\"10.1016/j.chemphys.2025.112619\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Laser-induced gratings (LIGs) were generated in neat O<sub>2</sub> at ambient temperature by photoexcitation of molecular species with nanosecond laser pulses at 1064 nm. LIGs were created at atmospheric pressure at different laser frequencies around that of the <sup><em>R</em></sup><em>R</em>(11) transition of the O<sub>2</sub>(<em>a</em> <sup>1</sup>Δ<sub><em>g</em></sub>, <em>υ</em> = 1) ← O<sub>2</sub>(<em>X</em> <sup>3</sup>Σ<sub><em>g</em></sub><sup>−</sup>, <em>υ</em> = 0) absorption band of O<sub>2</sub> monomers, and over a wide pressure range (1–130 bar) at a fixed frequency. LIGs were probed by diffracting continuous wave laser radiation.</div><div>The proposed modeling indicates that at small delays (0–2 μs) LIGs are formed, in addition to electrostriction, by “instantaneous” collisional exchange of energy between the molecular species and the environment resulting from radiation absorption by O<sub>2</sub>-O<sub>2</sub> dimols and the subsequent breakdown of the laser-excited species, with collisional emergence of electronically and vibrationally excited O<sub>2</sub> monomers. At large delays (20–1000 μs), LIGs are created by the “slow” collisional relaxation of the produced excited monomers.</div></div>\",\"PeriodicalId\":272,\"journal\":{\"name\":\"Chemical Physics\",\"volume\":\"593 \",\"pages\":\"Article 112619\"},\"PeriodicalIF\":2.0000,\"publicationDate\":\"2025-01-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Chemical Physics\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0301010425000205\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemical Physics","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0301010425000205","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Near-IR range laser generation of refractive index gratings in O2 gas: Role of mono- and bimolecular absorption and collisional relaxation
Laser-induced gratings (LIGs) were generated in neat O2 at ambient temperature by photoexcitation of molecular species with nanosecond laser pulses at 1064 nm. LIGs were created at atmospheric pressure at different laser frequencies around that of the RR(11) transition of the O2(a1Δg, υ = 1) ← O2(X3Σg−, υ = 0) absorption band of O2 monomers, and over a wide pressure range (1–130 bar) at a fixed frequency. LIGs were probed by diffracting continuous wave laser radiation.
The proposed modeling indicates that at small delays (0–2 μs) LIGs are formed, in addition to electrostriction, by “instantaneous” collisional exchange of energy between the molecular species and the environment resulting from radiation absorption by O2-O2 dimols and the subsequent breakdown of the laser-excited species, with collisional emergence of electronically and vibrationally excited O2 monomers. At large delays (20–1000 μs), LIGs are created by the “slow” collisional relaxation of the produced excited monomers.
期刊介绍:
Chemical Physics publishes experimental and theoretical papers on all aspects of chemical physics. In this journal, experiments are related to theory, and in turn theoretical papers are related to present or future experiments. Subjects covered include: spectroscopy and molecular structure, interacting systems, relaxation phenomena, biological systems, materials, fundamental problems in molecular reactivity, molecular quantum theory and statistical mechanics. Computational chemistry studies of routine character are not appropriate for this journal.