ROTATIONAL SPECTRUM OF A NEUROHORMONE - BETA-ALANINE

We have observed and assigned the rotational spectrum of beta-alanine using our Stark-modulated free-expansion jet spectrometer. Two conformers of beta-alanine have been identified, and they involve the same types of intramolecular interactions found in both gaseous glycine and alpha-alanine. Identification was based on a comparison of the results from parallel nb initio HF/6-31G** molecular orbital calculations and the observed rotational constants for the normal and N,N,O-d(3) isotopomers and N-14 quadrupole hyperfine multiplets. No evidence of a third conformer was observed despite the ab initio molecular orbital calculations predicting several energetically favorable conformations.