Direct observation of NF(X) using laser-induced fluorescence: Determination of the H + NH sub 2 branching ratio

• Published in: Journal of physical chemistry (1952) Vol. 93:23
• Main Authors: Heidner, R.F. III, Helvajian, H., Holloway, J.S., Koffend, J.B.
• Format: Journal Article
• Language: English
• Published: United States 16.11.1989
• Subjects: 400000 - Chemistry; 400500 - Photochemistry; ALKALI METAL COMPOUNDS; BRANCHING RATIO; DATA; ELEMENTS; EMISSION SPECTROSCOPY; ENERGY LEVELS; EXCITED STATES; EXPERIMENTAL DATA; FLUORESCENCE SPECTROSCOPY; FLUORIDES; FLUORINE COMPOUNDS; HALIDES; HALOGEN COMPOUNDS; HYDROGEN; INFORMATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MEASURING INSTRUMENTS; MEASURING METHODS; NONMETALS; NUMERICAL DATA; SODIUM COMPOUNDS; SODIUM FLUORIDES; SPECTROSCOPY
• ISSN: 0022-3654; 1541-5740
• DOI: 10.1021/j100360a019

For the first time, the product branching ratio for H + NH{sub 2} has been measured by using direct detection of the excited NF(a{sup 1}{Delta}) and the ground NF(X{sup 3}{Sigma}{sup {minus}}) states. NF(a{sup 1}{Delta}) was observed by its emission at 784 nm both from the 249-nm photolysis of NF{sub 2} and from the reaction of H atoms (produced from HBr photolysis at 193 nm) with NF{sub 2}. While NF(X{sup 3}{Sigma}{sup {minus}}) was easily detected by laser-induced fluorescence on the NF b{sup 1}{Sigma}-X{sup 3}{Sigma}{sup {minus}} transition following 249-nm NF{sub 2} photolysis, it was not observed following the H + NF{sub 2} reaction. This result leads to a lower limit for the NF(a) branching ratio, NF(a)/NF{sub tot} > 0.90 {plus minus} 0.03, in accord with previous results. The measured NF(a{sup 1}{Delta}) quantum yield from KrF photolysis of NF{sub 2}, {phi}{sub NF(a)} < 0.04 {plus minus} 0.02, also agrees with prior work. The NF{sub 2} photolysis quantum yield is observed to be unity, based on results from an HCl titration of the F atoms from the 249-nm photolysis of NF{sub 2}.