High-Resolution Fourier Transform Infrared Absorption Spectroscopy of the ν<sub>6</sub> Band of c-C<sub>3</sub>H<sub>2</sub>
Pradeep R. Varadwaj
Ryuji Fujimori
Kentarou Kawaguchi
10.1021/jp204068w.s001
https://acs.figshare.com/articles/High_Resolution_Fourier_Transform_Infrared_Absorption_Spectroscopy_of_the_sub_6_sub_Band_of_c_C_sub_3_sub_H_sub_2_sub_/2626462
The gas-phase high-resolution absorption spectrum of the ν<sub>6</sub> band of cyclopropenylidene (c-C<sub>3</sub>H<sub>2</sub>) has been observed using a Fourier transform infrared spectrometer for the first time. The molecule has been produced by microwave discharge in an allene (3.3 Pa) and Ar (4.0 Pa) mixture inside a side arm glass tube. The observed spectrum shows a pattern of c-type ro-vibrational transitions in which the Q-branch lines strongly and distinctly stand out in the spectrum. A combined least-squares analysis of the observed 216 ro-vibrational transitions together with 28 millimeter-wave rotational transitions from the previous study has resulted in an accurate determination of the molecular constants in the ν<sub>6</sub> state. The band center is found to be at 776.11622(13) cm<sup>–1</sup> with one standard deviation in parentheses, which is 2.3% lower than the matrix isolation value. The intensity ratio <i>I</i><sub>3</sub>(ν<sub>3</sub>)/<i>I</i><sub>6</sub>(ν<sub>6</sub>) obtained from the observed ν<sub>3</sub> and ν<sub>6</sub> bands, 1.90(9), is somewhat lower than the ratio estimated from ab initio (2.4–2.6) and DFT (2.8) calculations.
2011-08-04 00:00:00
side arm glass tube
absorption spectrum
Absorption Spectroscopy
3H
microwave discharge
intensity ratio
ν6 state
transition
ν6 bands
DFT
Pa
ν6 Band
Fourier
band center
matrix isolation value
ν6 band