Okabayashi T, Tanaka K, Tanaka T
Faculty of Science, Shizuoka University, 836 Oya, Shizuoka, 422-8529, Japan
J Mol Spectrosc. 1999 May;195(1):22-42. doi: 10.1006/jmsp.1999.7803.
Microwave spectrum of fluorocyanoacetylene (FCCCN) produced by a glow discharge in pentafluorobenzonitrile (C6F5CN) was observed using a source modulation spectrometer with a free-space absorption cell. Rotational transitions in the range from J = 9-8 to 53-52 were observed for the vibrationally excited states of nu4 (C&sbond;C stretch), nu5 (CCN bend), nu6 (FCC bend), nu7 (CCC bend), and their associated overtone and combination states up to about 1000 cm-1. Most of the vibrational states above 500 cm-1 are perturbed by rovibrational resonances. The effective vibration-rotation constant of the nu4 state has a negative value (-0.4 MHz), although a vibration-rotation constant generally has a positive value in the excited state of the stretching vibrational mode in a linear molecule. This anomalous behavior is interpreted as due to the rovibrational resonances between the nu4 and several nearby states. By the simultaneous analysis of the states concerned, the unperturbed vibrational energy and rotational constant of the nu4 state are obtained to be 686.50(76) cm-1 and 2068.2387(21) MHz, respectively, where the uncertainties correspond to one standard deviation. Copyright 1999 Academic Press.
使用带有自由空间吸收池的源调制光谱仪，观测了在五氟苯腈（C6F5CN）辉光放电中产生的氟代氰基乙炔（FCCCN）的微波光谱。观测到了ν4（C≡C伸缩）、ν5（CCN弯曲）、ν6（FCC弯曲）、ν7（CCC弯曲）振动激发态及其相关泛音和组合态（高达约1000 cm-1）从J = 9 - 8到53 - 52范围内的转动跃迁。500 cm-1以上的大多数振动态受到振转共振的扰动。尽管在线性分子的伸缩振动模式激发态中，振动转动常数通常为正值，但ν4态的有效振动转动常数却为负值（-0.4 MHz）。这种反常行为被解释为是由于ν4与几个附近态之间的振转共振所致。通过对相关态的同时分析，得到ν4态未受扰动的振动能量和转动常数分别为686.50(76) cm-1和2068.2387(21) MHz，其中不确定度对应于一个标准偏差。版权所有1999年，学术出版社。
