High-resolution Absorption Spectra of Acetylene in 142.8-152.3 nm

乙炔分子的吸收系列在 142.8 152.3 nm 的波长范围在凉下来喷气的条件下面被测量，与悦耳、高度解决的真空紫外(VUV ) 激光由二光子的反响的四波浪差别频率混合过程产生了。由于分子的横梁和更高的分辨率 VUV 激光的足够的震动、旋转的冷却效果，观察吸收系列展出更多不同光谱比在房间温度测量的以前的工作展示。三个震动的乐队作为拉长震动的进步的 C-C 对称被分配的专业(u 2= 0 2 )1 II 乙炔的 u 状态。在 148.2 nm 的观察肩膀山峰被分到 1 II 4 的第一个陪音乐队 > u 乙炔的状态。另外，二个部件， 4 o 2(μ1 II u ) 和 4 o 2(κ1 II u 在现在的吸收系列被建议到展览，由于他们的 Renner 出纳效果和转变选择统治。所有乐队起源和带宽随后被获得，并且带宽与颤动的刺激逐渐地被拓宽，一生减少，这被发现。

The absorption spectra of acetylene molecules was measured under jet-cooled conditions in the wavelength range of 142.8-152.3 nm, with a tunable and highly resolved vacuum ultraviolet （VUV） laser generated by two-photon resonant four wave difference frequency mixing processes. Due to the sufficient vibrational and rotational cooling effect of the molecular beam and the higher resolution VUV laser, the observed absorption spectra exhibit more distinct spectral features than the previous works measured at room temperature. The major three vibrational bands are assigned as a C-C symmetry stretching vibrational progress （v2=0.2） of the C^1Πu state of acetylene. The observed shoulder peak at 148,2 nm is assigned to the first overtone band of the trans-bending mode V4 of the C^1Πu state of acetylene. Additionally, the two components, 4^20（μ^1Π） and 4^20（k^1Πu）, are suggested to exhibit in the present absorption spectra, due to their Renner-Teller effect and transition selection rule. All band origins and bandwidths are obtained subsequently, and it is found that bandwidths are broadened and lifetimes decrease gradually with the excitation of vibration.