I_2分子B(v=43)能级在超音速射流中振动弛豫速率的定量测量

QUANTITATIVE MEASUREMENTS OF VIBRATIONAL RELAXATION RATES IN SUPERSONIC JETS OF I_2 B(v′=43) STATE

利用改变观察场位置的方法,用LIF法定量测量了超音速射流中I_2B(υ’=43)能极的振动弛豫速率.首次获得了Ar,N_2和CO等分子的驰豫截面.结果表明,低温射流中振动弛豫速率呈负温度关系,对载气He和H_2,主要弛豫过程是△υ=-1通道,但对Ar,N_2和CO等载气,多振动量子传输很显著,特别是对双原子分子,最可几弛豫通道不再是△υ=-1过程.这违反了能隙定律.这种现象可用亚稳态络合物的形成来解释。

A LIF technique that employs a varying view field has been developed to givequantitative measurement for the vibrational relaxation rates of I_2 B(v′=43) statein supersonic jets. The data for Ar, N_2 and CO are obtained for the first time. Theresults have shown that the measured vibrational relaxation rates in cold jets bear aninverse tempeature dependence. For He and H_2 carrier gases, the dominant relaxationprocess is the usual △v=-1 process. For Ar, N_2 and CO, however, the mostprobable relaxation pathway is no longer △v=-1 process, which apparently violatesthe energy gap law.These observations are adequately explained by a metastablecomplex formation mechanism.