THE $S_{1} - S_{0}$ FLUORESCENCE EXCITATION SPECTRUM OF FORMIC ACID

Abstract

The fluorescence excitation spectrum of formic acid monomer (HCOOH) has been recorded under jet-cooled conditions in the region, $268-257 nm$. A rotational analysis of the first four bands was used to establish the allowed and forbidden vibronic character of the transition as well as the torsional level splittings. A simulation of the torsional progression was carried out by ab-initio calculations at differing levels of approximation as a starting point for the refinement of the torsional and wagging potential functions.