Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University , Atlanta, Georgia 30322, United States.
J Phys Chem A. 2013 Dec 27;117(51):14028-41. doi: 10.1021/jp410315r. Epub 2013 Dec 9.
Predicting the results of collisions of polyatomic molecules with a bath of atoms is a research area that has attracted substantial interest in both experimental and theoretical chemistry. Energy transfer, which is the consequence of such collisions, plays an important role in gas-phase kinetics and relaxation of excited molecules. We present a study of energy transfer in single collisions of highly vibrationally excited allyl radical in argon. We evolve a total of 52 000 classical trajectories on a potential energy surface, which is the sum of an ab initio intramolecular potential for the allyl and a pairwise interaction potential describing the argon's effect on the allyl. The former is described by means of a permutationally invariant full-dimensional potential, whereas the interaction potential between allyl and argon is obtained by means of a sum of pairwise potentials dependent on nonlinear parameters that have been fit to a set of MP2/avtz counterpoise corrected ab initio energies. Results are reported for energy transfers and related probability densities at different collisional energies. The sensitivity of results to the interaction potential is considered and the potential is shown to be suitable for future applications involving different isomers of the allyl. The impact of highly efficient collisions in the energy transfer process is examined.
预测多原子分子与原子浴碰撞的结果是实验和理论化学都非常关注的研究领域。这种碰撞的结果——能量转移，在气相动力学和激发分子弛豫中起着重要作用。我们研究了高度振动激发的丙烯基自由基在氩气中的单次碰撞中的能量转移。我们在一个势能表面上演化了总共 52000 条经典轨迹，该势能表面是丙烯基的从头算分子内势能和描述氩对丙烯基影响的成对相互作用势能的总和。前者通过排列不变的全维势能来描述，而丙烯基和氩之间的相互作用势能则通过依赖于非线性参数的成对势能来获得，这些参数已拟合到一组 MP2/avtz 对消校正从头算能量。报告了不同碰撞能下的能量转移和相关概率密度的结果。考虑了结果对相互作用势能的敏感性，并表明该势能适合未来涉及丙烯基不同异构体的应用。还检验了能量转移过程中高效碰撞的影响。
