Premium
Ab initio thermal rate coefficients for H + NH 3 ⇌ H 2 + NH 2
Author(s) -
Nguyen Thanh Lam,
Stanton John F.
Publication year - 2019
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.21255
Subject(s) - thermochemistry , chemistry , ab initio , transition state theory , reaction rate constant , endothermic process , ab initio quantum chemistry methods , standard enthalpy of formation , thermodynamics , semiclassical physics , computational chemistry , standard enthalpy change of formation , kinetics , molecule , organic chemistry , physics , quantum mechanics , adsorption , quantum
The reversible reaction NH 3 + H ⇌ H 2 + NH 2 , which plays an important role in NH 3 fuel combustion, is studied with a theoretical approach that combines the high‐accuracy extrapolated ab initio thermochemistry (HEAT) protocol with semiclassical transition state theory (SCTST). The calculated forward reaction is endothermic by 11.8 ± 1 kJ/mol, in nearly perfect agreement with the active thermochemical tables (ATcT) value of 11.5 ± 0.2 kJ/mol. Using this improved thermochemistry yields better rate constants, especially at low temperatures. Experimental rate constants available from 400 to 2000 K for the forward and reverse reaction pathways can be reproduced (within 20%) by the calculations from first principles.