The FT microwave spectrum of benzo[b]thiophene: first application of a new heatable beam nozzle

Abstract

A new beam nozzle for a cavity FT microwave spectrometer has been developed that can be heated, even in close contact with massive aluminum mirrors, to temperatures up to 473 K (200°C). It has been used to evaporate a sufficient amount of benzo[b]thiophene to record and assign its rotational spectrum in the vibronic ground state of the normal and the ³⁴S isotopomer. Spectra of some excited vibrational states of the normal isotopic species were also found and assigned. In both cases rotational and quartic centrifugal distortion constants are reported.