分子角动量定位和定向布居的制备与探测

Preparation and Detection of Angular Momentum Orientation and Alignment of Molecule

利用线偏振和园偏振激光受激拉曼抽运技术 ,选择性地制备了C2 H2 线性分子电子基态中红外非激活振动模″v2 =1的单一转动态J″(X1∑+ g ,v″ =1,J″)的角动量定向布居和定位布居。并从线偏振及园偏振紫外激光诱导的A1 Au(′v3 =1)←X1∑ + g(″v2 =1)的电子跃迁荧光光谱中 ,直接测定了C2 H2 (X1∑ + g ,v″ =1,J″=4、7、8、9、10、11、12、13)的角动量定向布居值A( 1)0 为 0 .7～ 0 .8之间 ,对于J″ =2、3、4、5、6、7、8、9、11的角动量定位布居值A( 2 )0 为- 0 .7～ - 0 .9。这一结果表明 ,人们可利用上述激光抽运技术可控制C2 H2 分子在反应前的角动量空间布居。

The angular momentum orientation and alignment in single rotational states of the IR inactive vibrational mode (v″=1) in the electronic ground state of acetylene (X 1∑ + g, v″ 2=1,J″) has been selectively prepared by using circularly and linearly polarized laser stimulated Raman pumping. From the induced electronic transition fluorescence spectra by a circularly and linearly polarized UV laser, A 1* A u(v″=1)←X 1∑ + g (v″ 2=1), the A (1) 0 (orientation) of C 2H 2 (X 1∑ + g, v″ 2=1,J″=4,7,8,9,10,11,12,13) are measured directly in the range between 0.7 and 0.8. The A (2) 0 (alignment) for J″=2,3,4,5,6,7,8,9,11 is -0.7～-0.9. This results show that the spatial population of angular momentum of C 2H 2 molecule before reactions can be controlled by this laser pumping technique.