A spectroscopic potential energy surface for FCN

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• 作者：J. Zú ; ñ ; iga ; ^zuniga@um.es ; J.A.G. Picó ; n ; A. Bastida ; A. Requena
• 关键词：FCN ; 19F13C14N and 19F12C15N isotopologs ; Potential energy surface ; Optimal vibrational coordinates ; Vibrational terms and rotational constants
• 刊名：Journal of Quantitative Spectroscopy and Radiative Transfer
• 出版年：2012
• 期刊代码：70_00224073
• 类别：ch
• 出版时间：July, 2012
• 卷：113
• 期：11
• 页码：1155-1169
• 文件大小：282 K

摘要

A potential energy surface for the FCN linear molecule is obtained by nonlinear least-squares fit to the pure vibrational terms observed spectroscopically. The potential surface is expressed as a Morse-cosine expansion in valence coordinates, and the vibrational energy levels needed to carry out the fit are calculated variationally using a system of optimal generalized internal coordinates expressly determined for such a purpose. The quality of the potential energy surface fitted is checked by computing the vibrational terms G_v and the rotational constants B_v of the FCN molecule and its isotopologs ¹⁹F¹³C¹⁴N and ¹⁹F¹²C¹⁵N using a normal hyperspherical coordinate system which facilitates the assignments of normal modes quantum numbers to the vibrational energy levels and the subsequent comparison with the observed values. The spectroscopic FCN potential energy surface obtained is shown to reproduce the vibrational terms of the three molecular species well, and above all their rotational constants, thus endorsing the use of the potential to identify and characterize unobserved infrared bands of these species.