Rate constants, branching ratios, and energy disposal for NF(b,a,X) and HF(v) formation from the H + NF2 reaction

Abstract

paring the SCF total energies obtained by using the 4-31G basis set for propane,1,4 **propene,7 the n-propyl radical, and the hydrogen atom.8 In this manner, the computed energies for eq 1 and 2 are 37 and 82 kcal/mol, respectively.In contrast to the n-propyl radical is the energy required for C-H bond rupture in cubane and the cubyl radical, i.e., for reactions 3 and 4. Since experimental measurementsare not available for this system, the results of the ab initio calculations in this report will be used. When one uses the total energies for cubane, cubene, and the cubyl radical, the AH for rupture of a C-H bond in cubane, as indicated in eq 3, is found to be 91 kcal/mol. The AH for the ß C-H bond scission reaction in the cubyl radical, as shown in eq 4, is 106 kcal/mol. Because of the neglect of correlation energy in the SCF total energies, only two significant statements may be made about the energetics of reactions 3 and 4. The first is that the C-H bond energies in cubane and the cubyl radical are about equal. The second is that the energy required for ß C-H scission is clearly much (7) Total energy for propene was taken from

BiF/NF2 Kinetics Studies: Mechanism and Conversion Efficiency

“…21) suggests a BiF(X) bond energy of 100 kcal/mol. Thus, the most plausible source of ground state BiF is Bi( 4 S 3 / 2 )+ NF 2 --+ BiF(X0 + ) + NF(X31) (10) In addition, processes such as Reactions (4b) and (5b) may also contribute BiF(A0 + ) formation in the system by channeling excited state intermediates into the production cycle. The short radiative lifetime of the A0 + state quickly leads to an equilibrium concentration of ground state BiF We discount Reaction (5a) as being a major source of BiF(X0 + ) on the basis of experimental data (Ref.…”

“…8) and NF(a t A) (T = 5.5 sec) (Ref. 10) transition strengths are also important. Taking these and other factors into consideration, we estimate that errors in our absolutely calibrated data are on the order of a factor of 2 for Bi( 2 D 3 / 2 ) and NF(a'A) data which occur at nearly adjacent wavelengths.…”

A Theoretical Study of the Mechanism and Kinetics of F+N3 Reactions

“…The reactions of the fluorine atom with the azide radical N 3 are of great interest [1][2][3] and may have potential applications in new lasers. The following two reactions (i) and (ii) of F and N 3 are important: Normally, reaction (i) occurs on the singlet ( 1 A') potential energy surface (PES), whereas reaction (ii) occurs on the triplet ( 3 A'') PES, although nonadiabatic processes due to the intersection between 1 A' and 3 A'' surfaces are also possible.…”

“…[7,[9][10][11] A few experiments [8,9,12] indicate that reaction (i) is dominant, although there is no direct measurement of NF (X 3 S À ), which was predicted [9] to be no more than 10 % of the total NF product. Moreover, the thermal fragmentation of FN 3 A C H T U N G T R E N N U N G ( 1 A') was found [13] to yield the metastable NFA C H T U N G T R E N N U N G (a 1 D) with high efficiency. Electronic structure calculations on the intermediate FN 3 [14][15][16][17] and the F + N 3 reaction [18] are also available.…”

“…They performed very approximate CASSCF calculations (the active space is very small, including only six electrons in seven active orbitals) to explore the "conical intersection" using the Gaussian 98W programs and concluded that the singlet and triplet crossings may not cause predissociation of FN 3 …”