文献类型：期刊文献

中文题名：高位K_2分子与基态K原子及H_2分子间的激发转移

英文题名：Excitation Transfer between High-Lying States in K_2 in Collisions with Ground State K and H_2 Molecules

作者：沈晓燕[1];刘静[2];戴康[2];沈异凡[2]

机构：[1]华东理工大学化学与分子工程学院,上海200237;[2]新疆大学物理科学与技术学院,新疆乌鲁木齐830046

年份：2010

卷号：30

期号：2

起止页码：289

中文期刊名：光谱学与光谱分析

外文期刊名：Spectroscopy and Spectral Analysis

收录：CSTPCD;;EI(收录号：20101212786056);Scopus;北大核心:【北大核心2008】；CSCD:【CSCD2011_2012】；PubMed;

基金：国家自然科学基金项目(10664003)资助

语种：中文

中文关键词：激光光谱;能量转移;时间分辨荧光;截面;K2;H2

外文关键词：Laser spectroscopy; Energy transfer; Time-resolved fluorescence; Cross section; K2; H2

摘要：激光双光子激发K2至1Λg高位态，利用分子荧光光谱方法，研究了1Λg-3Λg间的碰撞转移截面。在纯K实验中，池温控制在553至603 K之间，K原子密度由光学吸收法测量得到。探测1Λg-11Σ＋u的直接时间分辨荧光的光强，它是一条纯指数衰减曲线，由此得到1Λ＋g态的有效寿命，有效寿命的倒数与K密度成线性关系，从直线的斜率得到1Λg态的猝灭截面为（2.5±0.3）×10-14 cm2，从截距得到辐射寿命为（20±2） ns。由3Λg→1 3Σ＋u转移荧光的时间分辨谱，用类似的方法得到3Λg的猝灭截面为（2.5±0.6）×10-14 cm2，辐射寿命为（16.0±3.2） ns。由1Λg→1 1Σ＋u与3Λg→1 3Σ＋u的时间积分强度比得到K2（1Λg）＋K→K2（3Λg）＋K的转移截面为（1.1±0.3）×10-14 cm2。在K2-H2碰撞实验中，池温保持在553 K，K密度为5×1015 cm-3，H2气压在40～400 Pa之间，其中K2-K碰撞效应是不能略去的，但可以用纯K结果扣除，得到K2（1Λg）＋H2←K2（3Λg）＋H2的碰撞转移截面为（2.7±1.1）×10-15 cm2。K2（3Λg）＋H2→K2（3Λg）以外态＋H2的猝灭截面为（6.8±2.7）×10-15 cm2。
Pure potassium vapor or K-H2 mixture was irradiated in a glass fluorescence cell with pulses of 710 nm radiation from an OPO laser, populating K2 （1Λg） state by two-photon absorption. Cross sections for 1Λg-11Σ＋u, transfer in K2 were determined using methods of molecular fluorescence. During the experiments with pure K vapor, the cell temperature was varied between 553 and 603 K. The K number density was determined spectroscopically by the white-light absorption measurement in the blue wing of the self-broadened resonance D2 line. The resulting fluorescence included a direct component emitted in the decay of the optically excitation and a sensitized component arising from the eollisionally populated state. The decay signal of time-resolved fluorescence from 1Λg→1 1Σ＋ transition was monitored. It was seen that just after the laser pulse the fluorescence of the photo- excited level decreased exponentially. The effective lifetimes of the lAg state can be resolved. The plot of reciprocal of effective lifetimes of the lag state against K densities yielded the slope that indicated the total cross section for deactivation and the inter- cept that provided the radiative lifetime of the state. The radiative lifetime （20±2） ns was obtained. The cross section for deacti- vation of the K2 （1Λg） molecules by collisions with K is （2.5±0. 3） ×10-14 cm2. The time-resolved intensities of the K2 3Λg→1 s 3Σ＋ （484 nm） line were measured. The radiative lifetime （16.0±3.2） ns and the total cross section （2. 5＋0. 6） ×10- 14 cm2 for deactivation of the K2 （3Λg） state can also be determined through the analogous procedure. The time-integrated intensities of 1Λg→1 1Σ＋u and3Λg→1 3Σ＋u transitions were measured. The cross section （ 1.1 ± 0. 3） ×10-14 cmz was obtained for K2（1Λg ） ＋ K→K2 （3Λg）＋K collisions. During the experiments with K-Hz mixture, the cell temperature was kept constant at 553 K. The Hz pressure was varied between 40 and 400 Pa. The effects of Kz-K collisions could not be neglected. These effects were sub- tracted out using the results of the pure K experiments. The cross section （2. 7±1.1）×10-15 cmz was obtained for K2 （1Λg）4- H2→K2 （3Λg）＋H2 collisions. The cross section is （6. 8±2. 7）×10--15 cm2 for K2 （3Ag）＋ H2→ states out of K2（3Λg）＋ H2 collisions.