Potential Practical Applications of Basic Research in Molecular Dynamics

Abstract

The chemical technology of the future will require a deeper knowledge of fundamental molecular‐dynamical processes. It will no longer suffice to be able to systematize (and even calculate) static properties of simple molecules in equilibrium or to produce tables of Arrhenius kinetic parameters characterizing the rate constants of a host of elementary chemical reactions. In order to make significant gains, in the sense of “breakthrough technology”, an intimate knowledge of basic molecular dynamical behavior will be needed. Such insight is derivable from a new class of experiments at the atomic and molecular level and from new theoretical‐computational approaches to molecular‐dynamical problems. To illustrate these new requirements, and the potential practical applications of an improved understanding at the basic level, examples are presented in the areas of combustion and atmospheric pollution, atmospheric and ionospheric chemistry, synthetic applications of selective excitation, lasers in chemistry and chemical‐to‐radiation energy conversion.

State-to-State Cross Sections and Rate Constants for Reactions of Neutral Molecules

“…The topic of state-to-state cross sections and rate constants has considerable theoreti cal and practical significance (27,(75)(76)(77).…”

“…This "textbook example" is the work of Chupka et al (26J in Ί 969 on the endoergic ionmolecule reaction H^iv) + He -> HeH + + H, from which a direct comparison could be made (27), at constant total energy, of the comparative effect of reagent vibration al energy vs. relative transiational energy upon the reaction cross section. Enhancements of more than two orders of magnitude were observed, which have been the subject of considerable theoretical attention (1_7, 28).…”

The Early Era of Laser-Selective Chemistry 1960∼1985: Roots of Modern Quantum Control

“…Another use of lasers for their potential excitation selectivity was in the study of molecular dynamics which was spurred by the development of pulsed tunable lasers in combination with molecular beam techniques and the improvement of computational capabilities in the 1970s. 59 Pulsed tunable lasers were thought to possess both the power as well as time and energy resolutions necessary to perform state-to-state dynamical studies of chemical reactions. The experimental concept was as follows: starting from molecules in the gas phase (i.e., to achieve a collision-free environment), a laser pulse would prepare a molecule in an initial quantum state in what was thought to be a reactive configuration.…”

“…Another use of lasers for their potential excitation selectivity was in the study of molecular dynamics which was spurred by the development of pulsed tunable lasers in combination with molecular beam techniques and the improvement of computational capabilities in the 1970s . Pulsed tunable lasers were thought to possess both the power as well as time and energy resolutions necessary to perform state-to-state dynamical studies of chemical reactions.…”