M. V. McCusker

Time resolved spectroscopy of xenon excimers excited by synchrotron radiation

Formation and decay rates of the lowest 0u+ and 1u states of Xe2*, excited by monochromatized synchrotron radiation from the Stanford storage ring (SPEAR), have been measured in pure xenon and in xenon–argon mixtures over the pressure range 102 to 104 Torr. The results are interpreted to yield radiative lifetimes (4.6±0.3 and 99±2 nsec, respectively, for vibrationally relaxed 0u+ and 1u molecules), vibrational relaxation rates [7×10−11 and 6×10−12 cm3/sec for Xe2* (1u) in collisions with xenon and argon, respectively], the Xe2* (0u+) three‐body formation rate from Xe(3P1) (5.3×10−32 cm3/sec), and rates for 0u+–1u mixing by collisions with xenon and argon.

Optical emissions of triatomic rare gas halides

We report in this paper the observation of optical emissions from triatomic rare gas halide molecules formed in excited high density rare gas–halogen mixtures. The broad‐band continuum emissions are identified as transitions between ionically bonded excited states (Rg+2X−) and repulsive covalent lower states that dissociate to ground state atoms. These emissions become predominant at high rare gas densities.

The possibility of an efficient tunable molecular iodine laser near 340 nm

We have observed intense band emissions between 340 and 344 nm from electron‐beam‐excited mixtures of high‐pressure argon gas and iodine vapor. This emission appears to be from molecular iodine. Using the 357.6‐nm band from an Ar/N2 mixture as a calibration, we have measured the fluorescence yield in this wavelength region to be 70±24%. From this we computed an over‐all fluorescence energy efficiency of 13±4%. Based on these observations, we suggest the feasibility of an efficient high‐energy electron‐beam‐pumped argon‐iodine laser. The gain of such an argon‐iodine laser should be comparable to that of the Ar/N2 second positive laser.

Electron‐beam‐controlled discharge HgCl* laser

Laser action of HgCl* was observed using an electron‐beam‐controlled discharge to pump a gas mixture of Hg/Cl2/Ar. An order of magnitude in the fluorescence enhancement was obtained. This gives an excitation efficiency by controlled discharge to be a factor of about 2 higher than that by direct electron‐beam pumping. In addition to the previously reported 5576‐A laser transition of HgCl*, a strong transition at 5584 A was also observed.

Gain measurements at 4416 Å on ArXeF* and Kr2F*

Recent measurements of radiation from certain rare gas–halogen mixtures have indicated the efficient production of broadband emitters in the visible. This paper reports a gain measurment at 4416 A in mixtures containing the two emitters tentatively identified as Kr2F* (λmax=4000 A and FWHM=900 A and ArXeF* (λmax=4600 A and FWHM=900 A). Attenuation of the 4416‐A probe laser during electron‐beam and electron‐beam‐sustained discharge excitation of 2–3 atm pressure mixtures of argon‐krypton‐fluorine and argon‐xenon‐fluorine indicates absorption only. The fluorescence signals from ArXeF* and XeF* (Ar/Xe/F2 mixture), and KrF* and Kr2F* (Ar/Kr/F2 mixtures) were monitored simultaneously with the absorption of the probe laser. Since the absorption was not proportional to the fluorescence of these species, it is tentatively concluded that it is due to another transient species. Typical absorptions of 10−3 cm−1 were observed at pump levels of 105 W cm−3. A knowledge of the absorption mechanism will be required to as...

Optical emissions from e‐beam‐excited gas mixtures

A high‐energy electron beam has been used to pump mixtures of rare gases and atmospheric gases or metal vapors. Bright optical emissions have been produced, and a table is given listing both the observed transitions and their relative intensities.