[en] Investigation on the production HgCd* in an e-beam preionized quasi-stable discharge have theoretically predicted and experimentally demonstrated that fluorescence efficiencies of approx. 50% can be achieved. Spectra of the emission for a discharge pumped mixture of Cd/Hg/Ne show the HgCd* continuum peaking at 470 nm and absolute fluence measurements indicate [HgCd*] approx. 10¹⁶ cm³. Measurements of the gain/absorption of this mixed metal exciplex show absorption of the HgCd* excited state across the entire band. The absorption peaked at the blue end of the continuum (457 nm) and decreased to approx. 1% in 40 cm at the red end of the continuum

[en] In an effort to reliably extend the understanding of KrF* lasers, we collected specific, detailed experimental data and carried out theoretical calculations to explore and document those issues we identified as likely to be important in the short pulse operating regime. These included the effects of: (1) fuel burnup, (2) electron quenching, (3) gain/absorption at high current densities, (4) photoionization, (5) accessibility of the lying levels of KrF by laser flux, (6) temperature on fluorescence efficiency

[en] A series of measurements characterizing an e beam pumped KrF* laser was carried out using a 200-nsec e-beam pulse having a rise time of 25 nsec at current densities up to 50 A/cm². These pump conditions are relevent for inertial confinement fusion laser drivers. The measurements include fluorescence efficiency, sidelight suppression of the fluorescence during lasing, and laser energy output over a wide range of laser parameters including: total density 0.5--2.0 amagats, temperature 300--400 K, fluorine density 0.15%--0.5%, current density 38--50 A/cm² and various mirror transmissions. This data was used to verify and refine a model of KrF* kinetics which was then used to estimate the performance of an angular multiplexed power amplifier suitable for laser fusion applications

[en] Investigations on the production of HgCd* and an e-beam preionized quasistable discharge have theoretically predicted and experimentally demonstrated that fluorescence efficiencies of approx.50% can be achieved. Spectra of the emission for a discharge pumped mixture of Cd-Hg-Ne show the HgCd* continuum peaking at 470 nm and absolute fluence measurements indicate [HgCd*]approx.10¹⁶ cm³. Measurements of the gain and/or absorption of this mixed metal exciplex show absorption of the HgCd* excited state across the entire band. The absorption peaked at the blue end of the continuum (457 nm) and decreased to approx.1% in 40 cm at the red end of the continuum

[en] Reactive scattering cross sections are measured for H(D)+Br₂→HBr(DBr)+Br by crossing a beam of hydrogen atoms with a beam of Br₂

[en] A crossed molecular beam study has been made of reactive cross section as a function of collision energy S/sub r/(E/sub T/) for all isotopic variants of the abstraction reaction H'+H''Br→H'H''+Br. The apparatus incorporates, for reagent preparation, a supersonic source of variable-energy H or D atoms, and, for product detection, a tunable vacuum ultraviolet laser to obtain laser-induced fluorescence of Br. The cross-section functions indicate that the threshold energy for reaction is <1 kcal/mol. At enhanced collision energy of E/sub T/ = 7 kcal/mol, the observed order of reactivity in the isotopic series designated (H',H'') was (D,H)> or approx. =(D,D)>(H,H)>(H,D). As noted in a previous report from this laboratory [Int. J. Chem. Kinet., Laidler Festschrift (in press)] the favorable kinematics for (D,H) as compared with (H,D) can be understood in terms of lengthened interaction time for D atom reaction (compared with H) and diminution in the time required for HBr (compared with DBr) to rotate into the preferred alignment for reaction. The effect is illustrated here in terms of a simple model of reaction. The experimental data obtained in this work at low collision energy, in conjunction with 300 K rate constants obtained by others, suggest that close to threshold, kinematic effects are supplanted by threshold effects, yielding S/sub r/(H,D)>S/sub r/(D,H), the inverse of the principal isotope effect at enhanced collision energy