scholarly journals Silane-initiated nucleation in chemically active plasmas: validation of density functionals, mechanisms, and pressure-dependent variational transition state calculations

2016 ◽  
Vol 18 (15) ◽  
pp. 10097-10108 ◽  
Author(s):  
Junwei Lucas Bao ◽  
Donald G. Truhlar
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
State Theory ◽  
Density Functionals ◽  
Variational Transition State Theory ◽  
Dependent Rate ◽  
Nanodusty Plasmas ◽  
Specific Quantum ◽  
Variational Transition State

Pressure-dependent rate constants for nucleation in nanodusty plasmas are calculated by variational transition state theory with system-specific quantum RRK theory.

scholarly journals Barrierless association of CF2and dissociation of C2F4by variational transition-state theory and system-specific quantum Rice–Ramsperger–Kassel theory

2016 ◽  
Vol 113 (48) ◽  
pp. 13606-13611 ◽  
Author(s):  
Junwei Lucas Bao ◽  
Xin Zhang ◽  
Donald G. Truhlar
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Dissociation Rate ◽  
State Theory ◽  
Variational Transition State Theory ◽  
Exchange Correlation ◽  
Direct Dynamics ◽  
Specific Quantum ◽  
Variational Transition State

Bond dissociation is a fundamental chemical reaction, and the first principles modeling of the kinetics of dissociation reactions with a monotonically increasing potential energy along the dissociation coordinate presents a challenge not only for modern electronic structure methods but also for kinetics theory. In this work, we use multifaceted variable-reaction-coordinate variational transition-state theory (VRC-VTST) to compute the high-pressure limit dissociation rate constant of tetrafluoroethylene (C2F4), in which the potential energies are computed by direct dynamics with the M08-HX exchange correlation functional. To treat the pressure dependence of the unimolecular rate constants, we use the recently developed system-specific quantum Rice–Ramsperger–Kassel theory. The calculations are carried out by direct dynamics using an exchange correlation functional validated against calculations that go beyond coupled-cluster theory with single, double, and triple excitations. Our computed dissociation rate constants agree well with the recent experimental measurements.

scholarly journals Predicting pressure-dependent unimolecular rate constants using variational transition state theory with multidimensional tunneling combined with system-specific quantum RRK theory: a definitive test for fluoroform dissociation

2016 ◽  
Vol 18 (25) ◽  
pp. 16659-16670 ◽  
Author(s):  
Junwei Lucas Bao ◽  
Xin Zhang ◽  
Donald G. Truhlar
Keyword(s):  
Experimental Data ◽  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
State Theory ◽  
Variational Transition State Theory ◽  
Temperature Range ◽  
Multidimensional Tunneling ◽  
Specific Quantum ◽  
Wide Pressure

We show that rate constants for dissociation of fluoroform computed by VTST/SS-QRRK agree excellently with definitive experimental data over a wide pressure and temperature range.

Computational study on the reaction of atomic chlorine with 1,2-dibromoethane (CH2BrCH2Br)

2013 ◽  
Vol 91 (11) ◽  
pp. 1123-1129 ◽  
Author(s):  
Ang-yang Yu
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Computational Study ◽  
Minimum Energy ◽  
State Theory ◽  
Basis Set ◽  
Stationary Points ◽  
Variational Transition State Theory ◽  
Variational Transition State

In this work, the reaction mechanism and kinetics of Cl + CH2BrCH2Br → products are theoretically investigated for the first time. The optimized geometries and frequencies of all of the stationary points and selected points along the minimum-energy path for the three hydrogen abstraction channels and two bromine abstraction channels are calculated at the BH&H-LYP level with the 6-311G** basis set and the energy profiles are further calculated at the CCSD(T) level of theory. The rate constants are evaluated using the conventional transition-state theory, the canonical variational transition-state theory, and the canonical variational transition-state theory with a small-curvature tunneling correction over the temperature range 200–1000 K. The results show that reaction channel 3 is the primary channel and the calculated rate constants are in good agreement with available experimental values. The three-parameter Arrhenius expression for the total rate constants over 200–1000 K is provided.

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