The NH2 scissors band of methylamine

• Published in: Canadian journal of physics Vol. 98; no. 6; pp. 560 - 566
• Main Authors: Gulaczyk, Iwona, Kręglewski, Marek, Asselin, Pierre, Pirali, Olivier, Kleiner, Isabelle
• Format: Journal Article
• Language: English
• Published: Ottawa Canadian Science Publishing NRC Research Press 2020
• Subjects: Cutting tools; Fourier transform spectrometers; Fourier transforms; High resolution; Infrared radiation; Low temperature; Polynomials; Quantum cascade lasers; Room temperature; Series expansion; Symmetry
• ISSN: 0008-4204; 1208-6045
• DOI: 10.1139/cjp-2019-0469

For the first time the ν4 NH2 scissors band has been assigned in a high-resolution infrared spectrum. A rotationally resolved spectrum of methylamine was recorded using two infrared spectroscopic techniques. A White-type multi-pass cell device coupled to the Bruker IFS 125 HR Fourier transform spectrometer was implemented on the AILES beamline at the SOLEIL synchrotron facility and a room-temperature spectrum of the whole band in the region of 1540–1710 cm−1 was recorded with a resolution of 0.001 cm−1. Then, a low-temperature high-resolution spectrum in the 1622.5–1655.6 cm−1 range of Q and R branches of the ν4 band was recorded using a quantum cascade laser spectrometer. Preliminary assignment was carried out in the NH2 scissors band region, and about 2200 transitions for K from 0 to 6 have been assigned for A, B, and E1 symmetry species. The simultaneous fit of assigned lines using a group-theoretical effective Hamiltonian was not successful; instead simple polynomial series expansions were used for each symmetry and K value.