Photodissociation of hydrogen chloride at 157 and 193 nm: Angular distributions of hydrogen atoms and fine‐structure branching ratios of chlorine atoms in the2Pjlevels

1992 ◽  
Vol 97 (11) ◽  
pp. 8210-8215 ◽  
Author(s):  
Kenichi Tonokura ◽  
Yutaka Matsumi ◽  
Masahiro Kawasaki ◽  
Shintaro Tasaki ◽  
Richard Bersohn
Keyword(s):  
Fine Structure ◽  
Hydrogen Chloride ◽  
Branching Ratios ◽  
Angular Distributions ◽  
Hydrogen Atoms ◽  
Chlorine Atoms ◽  
193 Nm

Fine structure branching ratios and Doppler spectroscopy of chlorine atoms from the photodissociation of alkyl chlorides and chlorofluoromethanes at 157 and 193 nm

1991 ◽  
Vol 94 (4) ◽  
pp. 2669-2674 ◽  
Author(s):  
Yutaka Matsumi ◽  
Kenichi Tonokura ◽  
Masahiro Kawasaki ◽  
Gen Inoue ◽  
Sunita Satyapal ◽  
...  
Keyword(s):  
Fine Structure ◽  
Branching Ratios ◽  
Chlorine Atoms ◽  
Doppler Spectroscopy ◽  
193 Nm

scholarly journals Electronic Energy Partitioning in Photodissociation

1983 ◽  
Vol 3 (1-6) ◽  
pp. 57-72
Author(s):  
Sherwin J. Singer ◽  
Karl F. Freed ◽  
Yehuda B. Band
Keyword(s):  
Fine Structure ◽  
Optical Transition ◽  
Sodium Hydride ◽  
High Energy ◽  
Branching Ratios ◽  
Electronic Energy ◽  
Angular Distributions ◽  
Relative Kinetic ◽  
Asymmetry Parameters ◽  
Potential Curves

Despite the apparent simplicity of photodissociation in diatomic molecules, some of the essential physics of this process is not understood when there is fine structure in the atomic photofragments. Previous theories cannot treat the branching ratios and angular distributions of the individual fine structure sublevels. We have developed a complete quantum mechanical theory of the effects of nonadiabatic couplings and of electronic angular momentum on the fine structure branching ratios, angular distributions, and polarization in diatomic photodissociation. When the photofragments separate with large relative kinetic energy, simple limiting expressions can be obtained for branching ratios and the symmetry parameters which characterize fragment angular distributions and polarized fluorescence from excited fragments. Information about the symmetry of the molecular states involved in the optical transition which dissociates the molecule may be deduced from fine structure branching ratios and asymmetry parameters in the high energy limit. At low relative kinetic energies where non-adiabatic couplings are crucial, cross sections and asymmetry parameters exhibit interesting behavior which intimately reflect the shape of the dissociative molecular surfaces. We employ the example of sodium hydride photodissociation to produce P2 excited sodium atoms as a model system because of the availability of ab initio potential curves and oscillator strength matrix elements. The low energy photodissociation cross section and angular distributions are shown to exhibit resonances which arise in part due to non-adiabatic spin–orbitand Coriolis couplings. Their energy dependence can therefore be utilized to probe the nature of potential curves which are not directly pumped in optical absorption processes and may therefore provide a unique spectroscopic means for measuring properties of these “dark” states.

The vacuum ultraviolet photolysis of hydrogen chloride. The role of the hot hydrogen atoms

1981 ◽  
Vol 55 (1-2) ◽  
pp. 9-15 ◽  
Author(s):  
A. Jówko ◽  
S. U. Pavlova ◽  
H. Baj ◽  
B. G. Dzantiev ◽  
M. Foryś
Keyword(s):  
Hydrogen Chloride ◽  
Vacuum Ultraviolet ◽  
Hydrogen Atoms ◽  
Ultraviolet Photolysis

PHOTOCHEMICAL SEPARATION OF MERCURY ISOTOPES: III. THE REACTION OF Hg2026(3P1) ATOMS, PHOTOEXCITED IN NATURAL MERCURY VAPOR, WITH HYDROGEN CHLORIDE

1959 ◽  
Vol 37 (5) ◽  
pp. 930-939 ◽  
Author(s):  
C. C. McDonald ◽  
J. R. McDowell ◽  
H. E. Gunning
Keyword(s):  
Emission Line ◽  
Hydrogen Chloride ◽  
Mercury Vapor ◽  
Pure Hydrogen ◽  
Hydrogen Atoms ◽  
Unsaturated Compounds ◽  
Depletion Effect ◽  
Flowing Hydrogen ◽  
Fast Flow ◽  
Static Conditions

An investigation has been made of the reaction of Hg2026(3P1) atoms, photoexcited in natural mercury vapor, with flowing hydrogen chloride at 28–30 °C. Emphasis has been placed on the effect of reaction parameters on the Hg202 content of the calomel product of the reaction.Under fast-flow conditions it has been found that the calomel product contains 44% Hg202, corresponding to an enrichment of 48% over the normal abundance of 29.8%.In the presence of unsaturated compounds such as butadiene and benzene the enrichment is markedly increased. With butadiene and benzene as addends, the maximum enrichments were 98% and 85% respectively.The reaction with pure hydrogen chloride can be explained in terms of the sequence:[Formula: see text]where HgN is natural mercury and M is a third body, including the wall.In the presence of unsaturated compounds (U), additional reactions are postulated to occur:[Formula: see text]The increased enrichment in the presence of unsaturated addends is explained by the reduced rate of formation of HgNCl through cleanup of chlorine and hydrogen atoms by reactions [6] and [7].Under static conditions, the pure hydrogen chloride reaction formed a calomel product of normal Hg202 abundance. This finding is explained as a localized depletion of the unexcited mercury in Hg202, through reaction [1]. With increasing linear flow rate the depletion effect gradually disappears and enrichments maximize at high flow rates.The Hg202 enrichment was found to be very sensitive to the wall temperature of the Hg202 source. In a 50:50 v/v mixture of hydrogen chloride and butadiene the enrichment was found to decrease from 68% to 24% as the lamp temperature was raised from 25.5 °C to 50 °C. The effect is explained by temperature broadening of the emission line leading to overlap of the emission line on absorption contours adjacent to that of Hg202.Both the rate of deposition of the calomel product and the Hg202 enrichment were found to depend upon the concentration of natural mercury in the gas stream for hydrogen chloride – butadiene mixtures. Optimum conditions corresponded to a slight supersaturation of the stream with mercury vapor.

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