NH ( X sup 3 @ sup minus , v =1--3) formation and vibrational relaxation in electron-irradiated Ar/N sub 2 /H sub 2 mixtures

Journal Article · Fri Mar 15 04:00:00 EST 1991 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.460616· OSTI ID:5881559

Dodd, J A; Lipson, S J; Flanagan, D J; Blumberg, W A.M. ^[1]; Person, J C; Green, B D ^[2]

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1. Geophysics Laboratory (AFSC)/OPI, Hanscom Air Force Base, Massachusetts 01731 (USA)
2. Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (USA)

Measurements of the dynamics of NH({ital X}{sup 3}{summation}{sup {minus}}, {ital v} =1--3), created in electron-irradiated N{sub 2}/H{sub 2} and Ar/N{sub 2}/H{sub 2} mixtures, have been performed. Time-resolved Fourier spectroscopy was used to observe NH({ital v}{r arrow}{ital v}--1) vibrational fundamental band emission. Time-dependent populations were then determined by spectral fitting. Subsequent kinetic fitting of these populations using a single-quantum relaxation model and a power-law dependence of {ital k}{sub {ital v}} on {ital v} yielded the following NH({ital v} =1--3) relaxation rate constants (units of 10{sup {minus}14} cm{sup 3} s{sup {minus}1}): {ital k}{sub {ital v}=1}(N{sub 2})=1.2{plus minus}0.5, {ital k}{sub {ital v}=2}(N{sub 2})=3.8{plus minus}1.5, {ital k}{sub {ital v}=3}(N{sub 2})=7.5{plus minus}2.5; {ital k}{sub {ital v}=1}(Ar)=0.2{plus minus}0.1, {ital k}{sub {ital v}=2}(Ar)=0.5{plus minus}0.2, {ital k}{sub {ital v}=3}(Ar)=0.8{plus minus}0.3; {ital k}{sub {ital v}=1}(H{sub 2}){le}50, {ital k}{sub {ital v}=2}(H{sub 2}){le}100, {ital k}{sub {ital v}=3}(H{sub 2}){le}150. In addition, the N{sub 2}/H{sub 2} data provided a measurement of the nascent excited vibrational state distribution resulting from the reaction N({sup 2}{ital D})+H{sub 2}{r arrow}NH({ital X},{ital v})+H. The ratio NH(1):NH(2):NH(3) was found to be 1.0:0.97:0.81 ({plus minus}0.28 in each value). Comparison of the observed nascent distribution with that of a statistical model suggests that the ratio NH(0):NH(1)=0.47. Using this derived distribution, we find the average product level {l angle}{ital v}{r angle} =1.6, and the fraction of the available product energy in vibration {l angle}{ital f}{sub {ital v}}{r angle} =0.44.

• OSTI ID: 5881559
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 94:6; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
ARGON
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DISPERSIONS
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FERMIONS
FLUIDS
GASES
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
KINETICS
LEPTONS
MIXTURES
NITROGEN
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADICALS
RADIOLYSIS
RARE GASES
RELAXATION
VIBRATIONAL STATES
YIELDS