On the reaction of ground-state nitrogen atoms with bromomethyl radicals: A computational study

The Reaction of Nitrogen Atoms with Methyl Radicals: Are Spin-Forbidden Channels Important?

“…It is also interesting to notice that CCSD(T)/ cc-pVTZ relative energies are systematically above the G2 ones (in most cases by 3-8 kcal/mol). In our previous studies on the CH 2 X( 2 A′) + N( 4 S) reactions, 14,16,18 we observed a similar behavior. We concluded that the discrepancy between the CCSD(T) and G2 energies is related, at least in part, to the description of N( 4 S), since the G2 method includes a higher-level empirical correction (HLC) which seems to be important for the description of N( 4 S).…”

“…9 The computed rate coefficient for the overall process at 298 K is 9.1 × 10 -12 cm 3 s -1 molecule -1 . This value is considerably higher than the rate coefficients obtained for the reactions of ground-state nitrogen atoms with halomethyl radicals, 15,16,18 which are in the range 3-13 × 10 -13 cm 3 s -1 molecule -1 . However, this value is 1 order of magnitude lower than the experimental 7 result for the N( 4 S) + CH 3 reaction, k)8.5 × 10 -11 cm 3 s -1 molecule -1 .…”

“…A kinetic computational study provides a rate coefficient for the overall process at 298 K of 9.1 × 10 -12 cm 3 s -1 molecule -1 , which is nearly 1 order of magnitude lower than the experimental 7 result for the N( 4 S) + CH 3 reaction, namely, k ) 8.5 × 10 -11 cm 3 s -1 molecule -1 . However the theoretically estimated rate coefficient is much larger than those computed for the reactions of ground-state nitrogen atoms with halomethyl radicals 15,16,18 , which are in the range 3-13 × 10 -13 cm 3 s -1 molecule -1 .…”

“…The overall features of the triplet PES for the N( 4 S) + CH 3 reaction are rather similar to those of the analogous reactions of ground-state nitrogen atoms with halomethyl radicals, N( 4 S) + CH 2 X (X being F, Cl, or Br). 14,16,18 In all cases the initial intermediate 3 I1, which is formed in a direct process without any barrier, is the most stable stationary point on the triplet PES and is located 60-70 kcal/mol below the reactants. The main difference concerns the nature of the most exothermic product.…”

“…In a series of recent papers, − we have provided computational studies of the reactions of ground-state and excited nitrogen atoms with halomethyl radicals (CH 2 F, CH 2 Cl, and CH 2 Br). Quantitative estimations of the rate coefficients and branching ratios have been provided.…”