VariFlex program

ChemRate program of Tsang and coworkers [102], and the VariFlex program [103] provide more general kinetics programs which include conventional RRKM theory with Eckart or other simple one-dimensional tunneling corrections. 

The Variflex program [35] was employed to calculate the dissociation rate constants. The predicted high- and low-pressure limiting rate constants for the decomposition reaction CIO4 S-CIO3 + O can be expressed by ... 

The reaction was shown to take place primarily over the singlet surface by two main chaimels producing HO2 + Cl and HCl + O2, with the former being dominant. The Variflex program was used for the rate constant calculation. The predicted total rate constant,... 

The rate constant for the association reaction channel (7c) was calculated in the temperature range from 200 to 2500 K and the pressure range from 1x10 to 7.6x10 Torr with the Variflex code [35], whereas those for channels (7b) and (7c) were computed with the ChemRate program... 

Programs such as Variflex [39], CHARMMRATE [40], or ChemRate [30] have the capability to calculate rate constants for reactions with no barrier, though both contain adjustable parameters and appear to work best if the rate constants can be anchored to experimental data. 

The PST calcrrlations of the association rates for the ion-molecule reactions can be carried out using programs such as VariFlex [86]. Though the main aim of this program is the calculation of rates for barrierless reactions, it also allows convenient estimates of the rates using PST. The program employs Monte Carlo phase space integration to evaluate the statistical functions. 

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