%0 DATA
%A Pradeep R., Varadwaj
%A Ryuji, Fujimori
%A Kentarou, Kawaguchi
%D 2011
%T High-Resolution Fourier Transform Infrared Absorption Spectroscopy of the ν_{6} Band of c-C_{3}H_{2}
%U 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
%R 10.1021/jp204068w.s001
%2 https://acs.figshare.com/ndownloader/files/4277144
%K side arm glass tube
%K absorption spectrum
%K Absorption Spectroscopy
%K 3H
%K microwave discharge
%K intensity ratio
%K ν6 state
%K transition
%K ν6 bands
%K DFT
%K Pa
%K ν6 Band
%K Fourier
%K band center
%K matrix isolation value
%K ν6 band
%X The gas-phase high-resolution absorption spectrum of the ν_{6} band of cyclopropenylidene (c-C_{3}H_{2}) 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_{6} state. The band center is found to be at 776.11622(13) cm^{–1} with one standard deviation in parentheses, which is 2.3% lower than the matrix isolation value. The intensity ratio *I*_{3}(ν_{3})/*I*_{6}(ν_{6}) obtained from the observed ν_{3} and ν_{6} bands, 1.90(9), is somewhat lower than the ratio estimated from ab initio (2.4–2.6) and DFT (2.8) calculations.