On the Rate Constant for the Association Reaction H + CN + Ar → HCN + Ar

Abstract

The importance of the chaperon mechanism (via ArCN or ArH complex formation) is investigated for the title reaction. All calculations employ the classical trajectory method to obtain the reactive cross sections while the equilibrium constants are estimated from statistical mechanics. A detailed analysis of the various approximations to the equilibrium constant is presented. Exploratory calculations based on the energy transfer mechanism are also reported. In addition, the decay rates of the HCN* and ArCN* species are examined in order to get insight on the detailed microscopic molecular dynamics. The chaperon mechanism is found to be important only at low temperatures, while the energy-transfer mechanism dominates for moderate and high ones.

Mode Specificity Study in Unimolecular Dissociation of Nonrotating H2O, DHO, and MuHO Molecules

“…2.3 Kinetic Models. In previous work, , we described non-RRKM behavior by assuming the following two-step mechanism: where B (C) stands for a molecular species not coupled (strongly coupled) with the reaction path, and the rate coefficients (denoted k 3 and k 4 to be consistent with the notation used in the present work) follow the relation k 3 < k 4 or k 3 ≪ k 4 . The calculated fraction of nondissociated species at each moment was then fitted to the form 31 where f B and f C are the fractions of B and C at time t , and and are the corresponding values for t = 0.…”

“…2.3 Kinetic Models. In previous work, 31,32 we described non-RRKM behavior by assuming the following two-step mechanism:…”

Evaluation of vibrational partition functions for polyatomic systems: quantum versus classical methods for H2O and Ar···CN

“…Both the momentum vector (p) and the inverse of the metric tensor (g~1) can also be written in partitioned form. In particular, p can be partitioned as pT \ (PT, JT) (35) where P is the momentum conjugate to Q, PT \ (P…”

New Double Many-Body Expansion Potential Energy Surface for Ground-State HCN from a Multiproperty Fit to Accurate ab Initio Energies and Rovibrational Calculations

“…Furthermore, due to its fundamental importance, several reaction dynamics studies involving HCN have been reported. [21][22][23][24] The most recent potential energy surface for HCN comes from the work of van Mourik et al, 13 who have based it on a fit to highly accurate ab initio data. Several analytical or semianalytical HCN/HNC potential energy surfaces had, however, been reported previously, 1,2,[25][26][27] some of which by explicitly fitting spectroscopic data.…”

“…It is also well established that HCN plays a key role in the combustion chemistry of nitrogen species, , where new reaction routes involving this molecule continue to be discussed (see, e.g., ref ). Furthermore, due to its fundamental importance, several reaction dynamics studies involving HCN have been reported. − …”