【摘要】 本文研究了CCl₃F分子红外多光子解离的激发频率特性。在延迟时间为～500ns的条件下,用激光诱导荧光方法测量了不同气压下CCl₃F分子的红外光解谱。当样品气压为0.5toor时,红移为6.3cm^-1,与本文按振转补偿模型计算得到的红移量理论值25cm^-1相差极大,而与转动能级热平衡粒子数分布极大所对应的跃迁的红移量十分接近。本文认为这是由于无碰撞条件下瓶颈效应对红移的影响。在高气压有碰撞情况下,红移有显著的增大。对瓶颈效应与分子结构之间的关系及解离阈值与激发频率之间的关系也作了简单的讨论。更多还原

【Abstract】 The dependence of the IR multiphoton dissociation yield of CCl₃F molecule on the frequency of the IR radiation exitation has been studied. The IRMPD spectra in different sample pressures have been measured by the method of LIF with a time delay of ～500ns. The experiment at low pressure of 0.5 torr demonstrated a redshift of 6.3 cm^-1. It is strikingly different from the 25cm^-1 redshift calculated theoretically in this paper according to the mechanism of rotational compensation for aaharmonicity of lower vibational transitions, but is rather close to the redshift of the transition from the level corresponding to the maximum of the rotational thermal distribution at 300K. This is because of the ro’ational relaxation bottleneck effect in the collisionless condition, considered in this paper. When in the collisional high pressure condition, there was a strong shift towards longer wavelengths. The relations between the photolysis frequency and the dissociation threshold and between the bottleneck effect and the molecular structure have been discussed.更多还原