Pure rotational spectrum of SnH4 in the vibrational ground state observed by infrared-radio frequency double resonance

Abstract

Pure rotational Q-branch transitions caused by the centrifugal-distortion-induced dipole moment were observed in the vibrational ground state of SnH4 by infrared-radio frequency double resonance using a tunable diode laser. Forty-nine double resonance signals were observed for 15 rotational transitions with 6≤J≤20 for seven isotopic species of Sn. The isotope effects on the transition frequencies were found to be negligible to the experimental accuracy of a few tens of kilohertz. The tensor centrifugal distortion constants were determined as follows: Dt =58 398.6±7.0 Hz, H4t =−4.297±0.046 Hz, and H6t =2.340±0.016 Hz.