Perkins Bradford G, Nesbitt David J
JILA, University of Colorado and National Institute of Standards and Technology, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, USA.
J Phys Chem A. 2009 Apr 23;113(16):4613-25. doi: 10.1021/jp811322y.
Quantum state-resolved energy transfer dynamics at the gas-liquid interface are explored through a comparison of classical molecular dynamics (MD) simulations and previously reported experimental studies (Perkins, B. G.; et al. J. Phys. Chem. A 2008, 112, 9234). Theoretically, large scale MD trajectory calculations have been performed for collisions of CO(2) with a model fluorinated self-assembled monolayer surface (F-SAMs), based on an explicit atom-atom interaction potential obtained from earlier theoretical studies (Martinez-Nunez, E.; et al. J. Phys. Chem. C 2007, 111, 354). Initial conditions for the simulations match those in the experimental studies where high-energy jet-cooled CO(2) molecules (E(inc) = 10.6(8) kcal/mol, <E(rot)> approximately 10 cm(-1)) are scattered from a 300 K perfluorinated liquid surface (PFPE) from a range of incident angles (theta(inc) = 0-60 degrees ). Nascent CO(2) rotational distributions prove to be remarkably well characterized by a simple two-temperature trapping-desorption (TD) and impulsive scattering (IS) model with nearly quantitative agreement between experimental and theoretical column integrated densities. Furthermore, three-dimensional (3D) quantum state resolved flux maps for glancing incident angles (theta(inc) approximately 60 degrees ) reveal broad, lobular distributions peaking strongly in the forward subspecular direction as cos(n)(theta(scat) - theta') with n approximately 5.6(1.2) and theta' approximately 49(2) degrees .
通过比较经典分子动力学(MD)模拟和先前报道的实验研究(Perkins,B.G.等人,《物理化学杂志A》2008年,112卷,9234页),探索了气液界面处量子态分辨的能量转移动力学。从理论上讲,基于早期理论研究(Martinez-Nunez,E.等人,《物理化学杂志C》2007年,111卷,354页)获得的显式原子-原子相互作用势,对CO₂与模型氟化自组装单分子层表面(F-SAMs)的碰撞进行了大规模MD轨迹计算。模拟的初始条件与实验研究中的条件相匹配,在实验中,高能喷射冷却的CO₂分子(E(inc)=10.6(8) kcal/mol,<E(rot)>约为10 cm⁻¹)从300 K的全氟液体表面(PFPE)以一系列入射角(theta(inc)=0-60度)散射。新生CO₂的旋转分布被证明可以通过一个简单的双温度俘获-解吸(TD)和脉冲散射(IS)模型得到很好的表征,实验和理论柱积分密度之间几乎达到了定量一致。此外,掠入射角(theta(inc)约为60度)的三维(3D)量子态分辨通量图显示出宽广的叶状分布,在向前的亚镜面方向上强烈峰值,其形式为cosⁿ(theta(scat)-theta'),其中n约为5.6(1.2),theta'约为49(2)度。