OCSO在固態Ar間質中的紅外吸收光譜

 羅文瑞

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摘　要

用輸出波長308 奈米 (308 nm) 的氯化氙(XeCl )準分子雷射照射含有臭氧(O₃ ) 和羰基硫(OCS) 的固態氬(Ar)間質後，位於2058.1, and 1032.9 cm^-1處產生新的紅外吸收譜線。根據同位素 ¹³C- and ¹⁸O-的實驗與理論計算結果，這些譜線被指派為OCSO 的C=O伸縮振動(C=O stretching)及S-O伸縮振動(S-O stretching) 模式。以密度泛函理論[density functional theory (B3LYP/6-311+G(3df))]預測OCSO兩種最穩定的同分異構物(isomer)：O(OCS)與OCSO。根據理論計算的結果，OCSO是最穩定的同分異構物。OSCO 為具有鍵長1.15 Å (C-O)、1.67 Å (C-S)、1.50Å (S-O) 與鍵角ÐCSO @ 110.40°的平面結構。OSCO比O(OCS) 大約穩定50.8 kJ mol^-1。理論計算所得到的OCSO振動波數(vibrational wave numbers)、紅外吸收強度、¹³C- and ¹⁸O-同位素位移與實驗的結果也相當吻合。

關鍵字：羰基硫,密度泛函理論,OCS,OCSO 

Isomer of OCSO: IR absorption spectra of OCSO in solid Ar

Wen-jui Lo

General Education Center , Tzu Chi College of Technology, 880, sec. 2,

Abstract

 

Irradiation of an Ar matrix sample containing O₃ and OCS with a XeCl excimer laser at 308 nm yielded new lines at 2058.1 and 1032.9 cm^-1. These lines are assigned to C=O stretching and S-O stretching modes of OCSO, based on results of ¹³C- and ¹⁸O-isotopic experiments and quantum-chemical calculations. These calculations using density functional theory (B3LYP/6-311+G(3df)) predict two stable isomers of OCSO:  According to calculations, OCSO is the most stable isomer. OSCO is planar, with bond lengths of 1.15 Å (C-O),1.67 Å (C-S), and 1.50Å (S-O) bond angle ÐCSO @ 110.40°; it is more stable than O(OCS) by ~50.8 kJ mol^-1. Calculated vibrational wave numbers, IR intensities, ¹³C- and ¹⁸O-isotopic shifts for OCSO fit satisfactorily with experimental results.

Keywords：carbonyl sulfide, density functional theory, OCS, OCSO  

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