Novel laser gain and time-resolved FTIR studies of photochemistry

Several techniques are discussed which can be used to explore laboratory photochemical processes and kinetics relevant to planetary atmospheres; these include time-resolved laser gain-versus-absorption spectroscopy and time-resolved Fourier transform infrared (FTIR) emission studies. The laser gain-versus-absorption method employed tunable diode and F-center lasers to determine the yields of excited photofragments and their kinetics. The time-resolved FTIR technique synchronizes the sweep of a commercial FTIR with a pulsed source of light to obtain emission spectra of novel transient species in the infrared. These methods are presently being employed to investigate molecular photodissociation, the yields of excited states of fragments, their subsequent reaction kinetics, Doppler velocity distributions, and velocity-changing collisions of translationally fast atoms. Such techniques may be employed in future investigations of planetary atmospheres, for example to study polycyclic aromatic hydrocarbons related to cometary emissions, to analyze acetylene decomposition products and reactions, and to determine spectral features in the near infrared and infrared wavelength regions for planetary molecules and clusters

New Results on Bs Mixing from LEP

The phenomenology of B_s^0 oscillations is reviewed along with the experimental strategy for observing them. Results of studies from ALEPH, DELPHI, and OPAL experiments are summarized with an emphasis on recent new results from ALEPH.Comment: 9 pages, 7 figures, submitted to Proceedings of Flavour Physics and CP Violation 200

The Zimm model applied to extended single polymers

A mean field theory is developed for the Zimm model and compared to the exact solution, computed numerically, for the case of a single extended polymer. An analytic calculation in the dumbbell approximation extends the preaveraging treatment. We find that the dynamic scaling of the preaveraged Zimm model is preserved for short polymers, but that the relaxation function is inhomogeneous in length for long polymers. These calculations can be applied to recent experimental results