Bartlett Nate C-M, Miller Daniel J, Zare Richard N, Alexander Andrew J, Sofikitis Dimitris, Rakitzis T Peter
Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.
Phys Chem Chem Phys. 2009 Jan 7;11(1):142-7. doi: 10.1039/b814133a. Epub 2008 Nov 25.
An aligned sample of HD(v = 1, J = 2, M(J) = 0) molecules is prepared under collision-free conditions using the S(0) stimulated Raman pumping transition. Subsequent coupling to the spins of the deuteron I(D) and the proton I(H) causes the initial degree of alignment to oscillate and decrease as monitored over the time range from 0-13 mus via the O2 line of the [2 + 1] REMPI E,F(1)Sigma-X(1)Sigma (0,1) band. The time dependence of the rotational alignment is also calculated using both a hierarchical coupling scheme in which the rotational angular momentum J is regarded first to couple to I(D), and then the resultant F(i) to couple to I(H), to form the total angular momentum F and a non-hierarchical coupling scheme in which the HD energy level structure is not assumed to be diagonal in the |I(H)(JI(D))F(i)FM(F)> basis set. The experimental data is in good agreement with the non-hierarchical calculation but not with the hierarchical calculation, as expected for this system. Additionally, we calculate the time dependence of the H and D nuclear spin polarizations.
在无碰撞条件下，利用S(0)受激拉曼泵浦跃迁制备了HD（v = 1，J = 2，M(J) = 0）分子的取向样本。随后，通过[2 + 1]共振增强多光子电离（REMPI）的O2线，在0 - 13微秒的时间范围内监测，与氘核I(D)和质子I(H)的自旋耦合导致初始取向程度振荡并降低，该跃迁属于E,F(1)Σ-X(1)Σ (0,1)带。还使用两种耦合方案计算了转动取向的时间依赖性：一种是分级耦合方案，其中先将转动角动量J与I(D)耦合，然后将所得的F(i)与I(H)耦合，以形成总角动量F；另一种是非分级耦合方案，其中在|I(H)(JI(D))F(i)FM(F)>基组中不假设HD能级结构为对角形式。正如该系统所预期的那样，实验数据与非分级计算结果吻合良好，但与分级计算结果不一致。此外，我们还计算了H和D核自旋极化的时间依赖性。
