对甲氧基苯甲腈的单色共振双光子电离光谱  

One color resonance two-photon ionization spectra of p-methoxybenzonitrile

作　　者：李鑫[1] 赵岩[1] 靳颖辉 王晓锐[2] 余谢秋 武媚[2] 韩昱行 杨勇刚[1] 李昌勇[1] 贾锁堂[1] 

机构地区：[1]量子光学与光量子器件国家重点实验室,山西大学激光光谱研究所,太原030006 [2]山西大学物理电子工程学院,太原030006

出　　处：《物理学报》2017年第9期115-121,共7页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2012CB921603);国家自然科学基金(批准号:61378039,61575115,11434007);长江学者和创新团队发展计划(批准号:IRT13076);量子光学与光量子器件国家重点实验室建设(批准号:2015012001-20)资助的课题~~

摘　　要：对甲氧基苯甲腈是一种重要的化学化工原料,本文采用超声分子束技术和共振多光子电离方法获得了对甲氧基苯甲腈的单色共振双光子电离光谱,基态S0到电子激发态S1的0←0跃迁被确定为(35549±2)cm^(-1),结合含时密度泛函理论计算结果对观察到的光谱进行了振动模式标识和描述.实验发现呼吸振动模非常易于激活,其基频和二次泛频光谱很强,三次泛频也可明确标识,观察到大量呼吸振动与其他正则模的结合振动,这是对甲氧基苯甲腈不同于常见的多原子分子的一个重要特性.这些结果为研究对甲氧基苯甲腈的里德堡态、动力学和零动能光谱等提供了重要的参考数据.p-methoxybenzonitrile is an important chemical and industrial material which has been widely used in many fields, such as medicine, chemistry, photoelectron, etc. In this paper, we use the technologies of supersonic molecular beam, resonance enhanced multiphoton ionization and time-of-flight mass spectrometer to obtain the high-resolution one color resonance two-photon ionization spectra of p-methoxybenzonitrile in a vibrational wavenumber range of 0-2400 cm-1 In order to analyze the experimental results, the theoretical calculations are performed. The molecular structure, energyI and vibration frequencies at the electronic excited state S] are computed with time-dependent density functional theory at the level of B3PW91/6-311 g＋＋＊＊. According to the calculated results, the observed bands are assigned by the method of Varsanyi and Szoke. The band origin of the S1 ← So electronic transition of p-methoxybenzonitrile is determined to be （35549 ± 2） cm^-1. A lot of vibrational bands of the electronic excited state S1 are observed. The results show that the vibrational modes of 9b, 6b, 15 and 1 are very easy to activate in a wavenumber range of 0-800 cm^-1. There are also a lot of intense bands in a wavenumber range of 800-1600 cm^-1. In addition to the fundamental vibrations, many combined vibrations between breathing and other fundamental vibrations are found. Several vibrations in this range are located at OCH3 and CN group. Most of the bands in a range of 1600-2400 cm-1 correspond to ones in the range of 800-1600 cm-1. Except for the bands appearing at 1664 and 2156 cm-1, which are assigned to 1511301 and v（CN） （CN stretching） respectively, the remaining bands in the range of 1600-2400 cm^-1 are assigned as the combined vibrations between the breathing and the corresponding modes in the range of 800-1600 cm^-1, i.e., the combined vibrations between the breathing overtone and other fundamental modes. Our theoretical calculations show that except for CN stretching vibration at 2162 cm^-1

关 键 词：对甲氧基苯甲腈 共振多光子电离 振动模式 基频和泛频 

分 类 号：TQ246.7[化学工程—有机化工] O657.3[理学—分析化学]