Acta Chimica Sinica ›› 1995, Vol. 53 ›› Issue (7): 637-644. Previous Articles     Next Articles

Original Articles

γ-吡啶甲酸及其同位素衍生物的谐性力场和振动光谱的从头计算研究

范康年;王文宁;夏琳;潘石麟   

  1. 复旦大学化学系
  • 出版日期:1995-07-15 发布日期:1995-07-15

Studies on the harmonic force field and vibrational spectra of γ-piconilic acid and its isotopic derivatives with ab initio calculations

FAN KANGNIAN;WANG WENNING;XIA LIN;PAN SHILIN   

  • Online:1995-07-15 Published:1995-07-15

The harmonic vibrational force field and the vibrational spectrum of γ-picolinic acid have been calculated by the ab initio gradient program TEXAS using a STO-4-21G basis set. The directly computed theoretical harmonic force field was scaled with a set of scaling factors transferred from related molecules to obtain a prediction of fundamental frequencies. The mean deviation between prediction and experimental IR spectrum of γ-picolinic acid in solid phase was 20cm^-^1(23cm^-^1 for in-plane modes, 11cm^-^1 for out-of-plane ones). The vibrational spectra of two isotopic derivatives of γ-picolinic acid (-C^1^6O~2D, -C^1^8O~2H) have been predicted with the SQM force field resulting from the transferred scaling factors. The calculated isotopic shifts are in good agreement with experimental data. A few scaling factors of in-plane modes were optimized to fit theoretical predicted frequencies to the experimental spectrum, reducing the mean deviation of in-plane modes to 15cm^-^1, and the total one to 14cm^-^1. The deviations and the assignments of some fundamentals were discussed.

Key words: AB INITIO CALCULATION, VIBRATIONAL SPECTRA, PYRIDINECARBOXYLIC ACID

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