The infrared spectra of gaseous oxalyl fluoride, oxalyl chloride, and oxalyl chloride fluoride, and the Raman spectra of liquid oxalyl fluoride and liquid oxalyl chloride have been measured. A satisfactory analysis of these spectra has been obtained for all three molecules on the basis of the trans isomer. An I.B.M. 7040 digital computer has been programmed to calculate the fundamental frequencies, normal coordinates, Urey-Bradley force constants, and potential energy distributions in Urey-Bradley space. The two electronic band systems of oxalyl fluoride whose origins are located at 3082 Å and 3340 Å have been photographed in absorption under low resolution. These band systems have been assigned ¹Aᵤ←¹A_g and ³Aᵤ←¹A_g transitions respectively, and have been partially analyzed in terms of the vibrational energy levels associated with the combining electronic states. / Thesis / Doctor of Philosophy (PhD)