High-resolution infrared spectroscopy of formamide and deuterated formamide in a molecular beam

Abstract

High-resolution infrared spectra of formamide and deuterated formamide (DCONH2) were collected by molecular-beam optothermal spectroscopy. The spectrum of formamide was found to be perturbed such that each rotational transition was split into two peaks. The splitting was absent in the spectrum of deuterated formamide. The large splitting in the spectrum of formamide (~0.7 cm−1) prevented an accurate deconvolution of the spectrum into zeroth-order bright and dark states. A list of the possible coupling modes is presented. The coupling, however, is not well represented as a simple coupling of two rigid rotors.