Developing Computational Methods and Studying Quantum Dynamics of Molecules and Clusters

弗拉基米尔·曼德尔什塔姆得到了理论和计算化学计划的资助，以开发研究分子和团簇中量子动力学的方法。他的核心技术是过滤器对角化方法，利用了切比雪夫动力学。将计算和分析单分子解离和复合过程的光谱。应用包括三原子物种，如二氧化氮、甲酰基和亚硝酰氢化物，重点放在非绝热效应上，包括Renner-Teller耦合和锥形相交。较长期的应用包括水和Ar/氟化氢团簇中的量子效应。基于精确的量子力学计算的化学动力学的理论研究只可能用于小分子。因此，这样的研究对于理解更大系统的动力学，以及将现有的近似理论与准确的量子结果联系起来，起到了基础性的作用。这里特别感兴趣的是具有混沌基础的经典动力学和高密度态的系统。具有不可分配光谱的复杂量子动力学即使在三原子分子的情况下也是一个挑战。

Vladimir Mandelshtam is supported by a grant from the Theoretical and Computational Chemistry Program to develop methods for the study of quantum dynamics in molecules and clusters. His central technique is the filter-diagonalization method, with the utilization of Chebyshev dynamics. Spectra will be computed and analyzed for unimolecular dissociation and recombination processes. Applications include triatomic species such as nitorgen dioxide, formyl radical, and nitrosyl hydride, with emphasis placed on non-adiabatic effects, including Renner-Teller coupling and conical intersections. Longer-term applications include quantum effects in water and argon/hydrogen fluoride clusters. Theoretical studies of chemical dynamics based on accurate quantum mechanical calculations are only possible for small molecules. Therefore such studies play a fundamental role in understanding the dynamics of much larger systems and in relating exising approximate theories to accurate quantum results. Of special interest here are systems with chaotic underlying classical dynamics and high densities of states. A complex quantum dynamics with unassignable spectra offers a challenge even in the case of triatomic molecules.