Synchrotron-based pure rotational spectroscopy of H13COOH

Abstract

The room-temperature far-infrared spectrum of 13C-labelled formic acid has been recorded at a resolution of 0.00096 cm−1. We assigned 1328 lines from 49 to 142 cm−1 to rotational transitions with quantum numbers that significantly extend the range beyond which was previously reported. We included these new lines in an analysis that involved fitting an extensive set of ground state molecular constants to line positions reported here and elsewhere. These constants allow for the accurate prediction of pure rotational line positions of H13COOH at temperatures that are relevant to Earth's atmosphere and various interstellar sources.