Near-IR range laser generation of refractive index gratings in O2 gas: Role of mono- and bimolecular absorption and collisional relaxation

IF 2 3区化学 Q4 CHEMISTRY, PHYSICAL Chemical Physics Pub Date : 2025-01-27 DOI:10.1016/j.chemphys.2025.112619

Dimitrii N. Kozlov

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Abstract

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(a ¹Δ_g, υ = 1) ← O₂(X ³Σ_g⁻, 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.

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来源期刊

Chemical Physics 化学-物理：原子、分子和化学物理

CiteScore

4.60

自引率

4.30%

发文量

278

审稿时长

39 days

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.