Electronic spectrum of the haloacetylenes. Part 2.—Bromoacetylene

Abstract

The electronic spectra of bromoacetylene and deuterobromoacetylene have been photographed from 2500 to 900 Å. Above 1730 Å two continua are observed, while below 1730 Å there are a number of Rydberg transitions with complicated vibrational structure. No Rydberg series have been identified but comparison with the spectrum of acetylene indicate an ionization potential of about 10.9 eV. A vibrational perturbation has been observed which leads to an apparent increase in C—C stretching-frequency on deuteration. A number of hot bands involving non-totally asymmetric vibrations have been observed indicating that the usual angular momentum selection rules do not hold.