Absolute Intensities of NH-Stretching Transitions in Dimethylamine and Pyrrole

详细信息    查看全文

• 作者：Benjamin J. Miller ; Lin Du ; Thomas J. Steel ; Allanah J. Paul ; A. Helena S枚dergren ; Joseph R. Lane ; Bryan R. Henry ; Henrik G. Kjaergaard
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：January 12, 2012
• 年：2012
• 卷：116
• 期：1
• 页码：290-296
• 全文大小：843K
• 年卷期：v.116,no.1(January 12, 2012)
• ISSN：1520-5215

文摘

Vibrational spectra of vapor-phase dimethylamine (DMA) and pyrrole have been recorded in the 1000 to 13000 cm^鈥? region using long path conventional spectroscopy techniques. We have focused on the absolute intensities of the NH-stretching fundamental and overtone transitions; 螖谓_NH = 1鈥? regions for DMA and the 螖谓_NH = 1鈥? regions for pyrrole. In the 螖谓_NH = 1鈥? regions for DMA, evidence of tunneling splitting associated with the NH-wagging mode is observed. For DMA, the fundamental NH-stretching transition intensity is weaker than the first NH-stretching overtone. Also, the fundamental NH-stretching transition in DMA is much weaker than the fundamental transition in pyrrole. We have used an anharmonic oscillator local mode model with ab initio calculated local mode parameters and dipole moment functions at the CCSD(T)/aug-cc-pVTZ level to calculate the NH-stretching intensities and explain this intensity anomaly in DMA.