HIGH-RESOLUTION INFRARED-SPECTROSCOPY OF FORMAMIDE AND DEUTERATED FORMAMIDE IN A MOLECULAR-BEAM

High-resolution infrared spectra of formamide and deuterated formamide (DCONH2) were collected by molecular-beam optothermal spectroscopy. T he spectrum of formamide was found to be perturbed such that each rota tional transition was split into two peaks. The splitting was absent i n the spectrum of deuterated formamide. The large splitting in the spe ctrum of formamide (similar to 0.7 cm(-1)) prevented an accurate decon volution of the spectrum into zeroth-order bright and dark states. A l ist of the possible coupling modes is presented. The coupling, however , is not well represented as a simple coupling of two rigid rotors.