Cold collisions between argon atoms and hydrogen molecules
Cold collisions between argon atoms and hydrogen molecules
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氩原子与氢分子之间的冷碰撞
DOI：
10.1103/physreva.65.032710
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发表时间：
2002
影响因子：
2.9
通讯作者：
R. C. Forrey
中科院分区：
文献类型：
--
作者：
Joseph Flasher;R. C. Forrey
通过考虑复杂的方阱势。我们证明，许多数值精确的耦合通道计算的重要功能，可以定性地理解在这个简单的模型。借助于复散射长度，可以构建动力学模型，用于描述振动或旋转激发的捕获分子2的弛豫。弛豫可能是由于直接碰撞猝灭或货车德瓦耳斯络合物的形成和衰变。当复合物的端对端角动量为零并且振动伸缩量子数是允许复合物被束缚的最大可能整数时，可以使用有效射程理论来计算预解离的寿命2，21。数值试验证实了有效射程理论的可靠性进行He H2只支持一个单一的束缚态。在目前的工作中，我们进行了类似的测试Ar H2存在几个束缚态。先前已经证明，货车德瓦耳斯络合物的最弱结合态的预解离受到在原子-硅藻碰撞中发现的相同准共振振动-旋转能量转移的影响。还示出了闭合准谐振通道阈值的接近度对寿命21提供了强烈的影响。在目前的工作中，我们研究的分析结构的阈值行为得到使用两个参数化的Ar-H2势能戈伊表面和调查是否准共振动力学有任何影响更深的束缚态的复杂。该文件的组织如下：在第二节。在第二章中，我们描述了势能面的一些定性特征，这些特征对我们的研究很重要。第三节提供了一个审查的标准的紧耦合形式主义，我们用来获得一个广泛的数据库的振转速率系数和predissociation寿命的参数化表面。节中IV，我们演示了如何复杂的方阱势可以用来提供定性描述的几个关键结果，发现从数值精确的耦合通道计算。这些结果见第2节。五、我们的调查结论见第二节。六.
by considering a complex square-well potential. We demonstrate that many of the important features of a numerically exact coupled-channel calculation may be qualitatively understood in terms of this simple model. W ith the aid of the complex scattering length, a kinetic model may be constructed for describing the relaxation of vibrationally or rotationally excited trapped molecules 2 . The relaxation may be due to direct collisional quenching or to the formation and decay of van der Waals complexes. When the end-over-end angular momentum of the complex is zero and the vibrational stretching quantum number is the lar gest possible integer that allows the complex to be bound, it is possible to use effective range theory to compute the lifetimes for predissociation 2,21 . The numerical tests that confirmed the reliability of the effective range theory were performed on He H 2 that supported only a single bound state. In the present work, we perform similar tests for Ar H 2 where several bound states exist. It was previously demonstrated 21 that predissociation of the most weakly bound state of a van der Waals complex is influenced by the same quasiresonant vibration-rotation energy transfer that is found in atom-diatom collisions 22 . It was also shown that the proximity of closed quasiresonant channel thresholds provides a strong influence on the lifetimes 21 . In the present work, we study the analytic structure of the threshold behavior obtained using both parametrizations of the Ar-H2 potential-ener gy surface and investigate whether quasiresonant dynamics has any influence on the more deeply bound states of the complex. The paper is organized as follows: in Sec. II, we describe a few qualitative features of the potential-energy surface that are important for our investigations. Section III provides a review of the standard close-coupling formalism that we used to obtain an extensive database of rovibrational rate coefficients and predissociation lifetimes for both of the parametrized surfaces. In Sec. IV, we demonstrate how a complex square-well potential may be used to provide a qualitative description of several of the key results that are found from the numerically exact coupled-channel calculations. These results are presented in Sec. V. Conclusions to our investigation are given in Sec. VI.