中文摘要：

以纳秒Nd：YAG激光器的四倍频（266nm）为激发源，利用门选通增强光学多通道光谱分析仪（OMA），研究了SO2分子第一激发带粒子的荧光辐射与碰撞弛豫相结合的复杂退激发过程。通过对SOz分子第一激发带的激发及碰撞弛豫过程的时间断层扫描分析，可以将激光诱导色散荧光谱中以305．6nm、337．2nm为中心的荧光包络和以424．7nm为中心的规则序列分剐归属于B^1B1、A^1A2低振动能级和口3B。基振动能级到基电子态X^1A1不同振动能级的荧光跃迁，由此可以确定大气污染气体SO2的诱导荧光的灵敏检测波长为425nm；由规则序列的实验数据可以计算出SOz分子基电子态X^1A1的对称振动和弯曲振动模式的基振动角频率分别为ω1=1151．8±0．6cm^-1和ω2=517．8±0．6cm^-1,两振动模式的非谐性常数分别为X^11=8±0．6cm^-1和X^22=9．2±0．6cm^-1．

英文摘要：

The paper presented one study on the complicated de-excitation process of the first-excited band of SO2 molecule, including fluorescence radiation and collision relaxation, using gated enhanced optical multi-channel spectrum analyzer （OMA） and the quadruple harmonic output （266 nm） of a nanosecond pulsed Nd. YAG laser as excitation source. The time tomographic scanning results showed that the fluorescence spectrum envelopes centered in 305.6 nm and 337.2 nm and the regular fluorescence lines centered in 424.7 nm in the laser induced dispersive fluorescence spectra （LIDFS） were attributed to transitions to the different vibrational levels of ground electronic state X1A1 from low vibrational levels of BIB1, A1A2 and the ground vibrational level aaB1 respectively. The sensitive detection wavelength （425 nm） of SO2 gas was confirmed by the experiment. The harmonic frequencies of the symmetry stretch vibration （ωl =1151.8 cm^-1 ±0. 6cm^-1） and the bend vibration （ω2=517.8 cm^-2 ±0.6 cm^-1） of X1A1 state were also calculated from the experimental data. The anharmonic constants of stretch vibration mode and the bend vibration mode are X^11= 8±0.6 cm^-1 and X^22= 9.2±0. 6 cm^-1 respectively.