Assignment of the methanol OH-stretch overtone spectrum using the pattern recognition method

Abstract

We present the measurement and analysis of the 2OH stretching band of methanol between 7165 cm⁻¹ and 7230 cm⁻¹ cooled down to 26 ± 12 K in a buffer gas cooling experiment. Measurements were performed with a cavity ring-down spectrometer having a detection limit α_min = 2 × 10⁻¹⁰ cm⁻¹. A total of 350 rovibrational transitions were assigned and 62 rovibrational transitions were tentatively assigned. This assignment was performed using the pattern recognition method developed by Rakvoský et al. [Phys. Chem. Chem. Phys., 2021, 23, 20193–20200]. In this work, we extended their method by using information on the relative intensities of the transitions to add one criterion to the validation of the assignments, allowing us to firmly assign 188 additional rovibrational transitions and to tentatively assign 14 more compared to the ir work.