High resolution FT-IR spectra of the ν1, ν2, and ν3 bands of H 12CP and of the ν1 and ν2 bands of H 13CP

Abstract

A sample of HCP (phosphaethyne) was synthesized by pyrolysis of CH 3PCl 2 (dichloromethylphosphane). H 13CP was present in natural abundance. High resolution spectra were measured with a BRUKER IFS 120 HR Fourier transform spectrometer using a 3-m absorption cell, and a White-type cell with absorption path lengths up to 19.68 m. The wavenumber regions measured were 400–725, 1200–1850 and 2500–3600 cm −1 with resolutions of 0.0018, 0.0024 and 0.0048 cm −1, respectively. In the lowest wavenumber region, the ν 2 fundamental band, hotbands from v 2 = 1,2,3 and v 3 = 1, as well as one Fermi-resonance induded band, ( v 1v l 2 2v 3) = (00 Oc 1) « (01 le 0 ), were assigned and analysed. In the second region, the fundamental band ν 3, its hot band from v 2 = 1, and the overtone of ν 2 and its hot bands could be measured, and in the third region. ν 1 and its hot bands. The fundamental and overtone bands of the bending vibration of H 13CP, and its hotbands from v 2 = 1 and 2, as well as the ν 1 fundamental were also assigned and analysed. The bands observed for the first time in this work are: for H 12CP: (011)-(001), (001)-(010), (030)-(020), (011)-(010), (040)-(030), and for H 13CP: (020)-(010). (020)-(000). Spectroscopic constants including Fermi resonance parameters for H 12CP and H 13CP of the effective Hamiltonian for linear molecules are given.