Fourier transform infrared (FTIR) spectrum (250–3800 cm−1) of formaldoxime-13C (13CH2NOH) and rovibrational analysis of its [formula omitted] band

Abstract

The Fourier transform infrared (FTIR) spectrum of formaldoxime-13C (13CH2NOH) was recorded in the 600–3800 cm−1 region with a resolution of 0.50 cm−1 to identify its fundamental and overtone bands and to measure their relative infrared band intensities. Furthermore, the high-resolution (0.00096 cm−1) FTIR spectrum of the ν12 band of 13CH2NOH was recorded at the Australian Synchrotron in the 250–600 cm−1 region for a rovibrational analysis. A total of 1506 infrared (IR) transitions of the C-type ν12 band were fitted using the Watson's A-reduced and S-reduced Hamiltonians in the Ir representation with a root-mean-square (rms) deviation of 0.000364 cm−1 for both fits. From the rovibrational analysis, the v12 = 1 state rovibrational constants up to one sextic centrifugal distortion term were derived for the first time. The band center of the ν12 band of 13CH2NOH were found to be 397.365846(32) cm−1 in the A-reduced Hamiltonian. The ground state rovibrational constants up to one sextic term were improved with higher accuracy by fitting 1374 ground state combination differences (GSCDs) derived from the IR transitions of the ν8 and ν12 bands of 13CH2NOH, together with two previously reported microwave frequencies. Furthermore, a comparison of the experimental vibrational frequencies, IR band intensities, rovibrational constants (v12 = 1 and ground states) of 13CH2NOH and those derived from theoretical calculations at two levels of theory: B3LYP and MP2 with cc-pVTZ basis set were made. Close agreement was found for the calculated and experimental rovibrational constants of 13CH2NOH for both ground and v12 = 1 states.