Probing Quantum Dynamics of Elementary Chemical Reactions via Accurate Potential Energy Surfaces

Abstract

Potential Energy Surface / Reaction Dynamics / Elementary Chemical Reaction / Transition StateProbing reaction potential energy surfaces is crucial for understanding chemical reaction dynamics and kinetics. The fundamental importance of the potential energy surface in understanding chemical reactivity was pointed out in the pioneering paper by Eyring and Polanyi in 1931 [1]. Accurate potential energy surfaces, however, are difficult to obtain. In the last few decades, more accurate quantum chemistry methods to calculate potential energy surfaces became available. In addition, quantum dynamics methods were also developed and allow us to study simple chemical reactions from first principles. Furthermore, modern crossed molecular beams studies provide an excellent testing ground for developing an accurate physical picture of elementary chemical reactions, through interplay between theory and experiment. In this paper, we review recent developments in the study of reaction dynamics of elementary chemical reactions through combined experimental and theoretical efforts. We will provide two examples to demonstrate the importance of accurate potential energy surfaces in understanding the essentials of reaction dynamics. One is the simplest chemical reaction: the H + H 2 reaction, the other is the benchmark system for chemical reaction resonance: the F + H 2 reaction. Through these studies, dynamics of chemical reactions can be understood at the most fundamental level.

Isotope-Dependent Rotational States Distributions Enhanced by Dynamic Resonance States: A Comparison Study of the F + HD → HF(vHF = 2) + D and F + H2 → HF(vHF = 2) + H Reaction

“…Extensive study does indicate that the current PES is more accurate than previous version. 24,29 The current PES does not need any scaling factor to the original ab initio energy points.…”

The Dynamics of Highly Vibrationally Excited CO Scattered from Metal Surfaces

“…Since the vibrational states v ≤ 13 are not detected, the total number of scattered molecules N sca cannot be determined as mentioned in Equation 4. 13. In order to determine N sca , the silver surface is chlorinated which passivates the surface and suppresses vibrational relaxation.…”

“…The importance of accurate PES in understanding chemical reactivity cannot be overstated [13]. For molecule-molecule interactions, theoretical models attain such a high level of accuracy that the comparison to experiment requires the use of advanced experimental techniques such as velocity-map imaging (VMI) [14,15], Rydberg atom tagging (RAT) [16], or Stark deceleration of molecular beams [17,18].…”