Structural deformation of nitro group of nitromethane molecule in liquid phase in an intense femtosecond laser field

• 来源期刊: 中国物理B（英文版）
• 关键词: coherent anti-Stokes Raman spectroscopy (CARS) spectra structural deformation intense laser field liquid nitromethane
• 年，卷（期）: 2017,（9）
• 页码范围: 228-233
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/1674-1056/26/9/094208

摘要

The structural deformation of NO2 group induced by an intense femtosecond laser field of liquid nitromethane (NM) molecule is detected by time-and frequency-resolved coherent anti-Stokes Raman spectroscopy (CARS) technique with the intense pump laser.Here,we present the mechanism of molecular alignment and deformation.The CARS spectra and its FFT spectra of liquid NM show that the NO2 torsional mode couples with the CN symmetric stretching mode and that the NO2 group undergoes ultrafast structural deformation with a relaxation time of 195 fs.The frequency of the NO2 torsional mode in liquid NM (50.8±0.3 cm-1) at room temperature is found.Our results prove the structural deformation of two groups in liquid NM molecule occur simultaneously in the intense laser field.