Rotational analysis of the (2000) stretching vibrational band system of 116SnH4

Abstract

A high resolution Fourier transform infrared spectrum, resolution (FWHM) 10.5×10−3 cm−1, of the (2000, A1/F2) stretching vibrational band system of 116SnH4 has been measured and analyzed in detail up to J=20. The rotational levels of the two vibrational states A1 and F2 are treated simultaneously by including vibration–rotation coupling terms in the Hamiltonian. 1290 infrared transitions from the ground vibrational state to the excited (2000) states have been included as data in the least squares optimization of 21 Hamiltonian parameters. The standard deviation of the fit obtained is 1.1×10−3 cm−1. The upper state vibrational energy level separation has been determined to be 0.0908 (5) cm−1 with the A1 state being higher in energy than the F2 state. The effective rovibrational parameters are found to satisfy closely the local mode constraints.