The reactive flux method applied to complex isomerization reactions: Using the unstable normal mode as a reaction coordinate
نویسندگان
چکیده
A basic problem when calculating reaction rates using the reactive flux method is the introduction of a reaction coordinate. In this paper we show that it is advantageous to define a reaction coordinate by means of the unstable normal mode of the saddle point of the potential energy surface. This particular choice is made since it yields a high transmission function. Moreover, the reaction coordinate is calculated via a rapidly converging algorithm, and its derivative, which is needed in constrained runs, is calculated analytically. Calculations on the transmission coefficient of the isomerization of n-butane are in good agreement with results published by others. Runs with an isomerizing calix@4#arene in vacuo produce a very high transmission coefficient, as is the purpose of the reaction coordinate. The same molecule is also studied in chloroform. © 1997 American Institute of Physics. @S0021-9606~97!51513-3#
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