The Electronic Absorption Spectrum of Thioformaldehyde (CH₂S)

Abstract

The ¹A₂ ← ¹A₁ (π* ← n) electronic absorption spectrum of thioformaldehyde vapour has been investigated. The six excited state fundamental frequencies for both CH₂S and CD₂S are determined from the vibrational analysis. The three rotation constants and three symmetric top distortion constants for the 0⁰₀, 4¹₀ and 3¹₀4³₀ bands of CH₂S and the 0⁰₀, 4¹₀ and 5¹₀ bands of CD2S are determined from a least squares rotational analysis of these bands. The rotational constants of the 0⁰₀ and 4¹₀ bands of CH₂S and CD₂S are used to determine the structure of the molecule in the excited state.