Vibrational relaxation of S2(a1Δg, υ=1–9) by collisions with He

• Published in: Chemical physics letters 2016-07, Vol.657, p.95-101
• Main Authors: Yamashita, Jun, Goto, Hiroki, Fujihara, Keigo, Hara, Ayano, Kohguchi, Hiroshi, Yamasaki, Katsuyoshi
• Format: Article
• Language: English
• Subjects: Disulfur; Energy gap law; Integrated profiles method; Laser-induced fluorescence; Vibrational relaxation
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2016.05.063

[Display omitted] •The collision efficiencies of vibrational relaxation of S2(a1Δg) by He are 10−3–10−2.•Vibrational relaxation rates of S2(a1Δg, υ) by He increase superlinearly with υ.•Relaxation of S2(a1Δg)+He system is much faster than that of O2(X3Σg-)+He system.•The V–T processes of S2(a), O2(X), NO(X), and CO(X) by He are correlated by the gap law. Vibrationally excited S2(a1Δg, υ=1–10) was generated by the S(1D)+OCS reaction and detected with dispersed laser-induced fluorescence (LIF) via the f1Δu–a1Δg transition. The time profiles of the vibrational levels of interest were recorded at varying pressures of He. A kinetic analysis made by the integrated profiles method has given the rate coefficients for vibrational relaxation of S2(a1Δg,υ=1–9) by collisions with He. The energy gap law nicely correlates the probabilities of vibrational energy transfer per collision from S2(a1Δg), O2(X3Σg-), NO(X2Π), and CO(X1Σ+) to He.