Long distance effects in non-leptonicK decays revisited

We amplify our earlier approach to non-leptonicK decays and reconsider it in the light of recent theoretical developments. We point out some interesting similarity, as well as differences from, recent treatments using 1/N.     

Ionisation of cyanate ions in solution

The He(I) photoelectron spectra of the ions OCN^? and SCN^? in adiponitrile solution have sharp bands peaking at 8.3 and 7.1 eV. In acetonitrile solution, the N-methylpyridazinium salts possess UV/visible absorption bands at 4.16 (OCN^?), 3.64 (SCN^?) and 3.37 eV (SeCN^?); these are assigned as electron transfers from anion to cation. The conclusion is drawn that the near-UV absorption bands of the anions are caused by electron transfers to the solvent.     

The flash photolysis—shock tube technique using atomic resonance absorption for kinetic studies at high temperatures

A flash photolysis-shock tube technique is described for making kinetic measurements at high temperature. Coupled with sensitive atomic resonance absorption detection, this method allows bimolecular rate constants for atom-molecule reactions to be measured directly under conditions free from kinetic complications. Experiments were performed in the reflected shock regime, and the temperature and density were calculated using ideal shock wave theory in this initial work. Results for the reaction of atomic hydrogen with ammonia are presented to illustrate the potential of the technique. The values of the Arrhenius rate parameters found in these experiments, 900 K ≤ T ≤ 1850 K, were A = (1.14 ± 0.12) × 10^?10 cm³ molecule^?1 s^?1 and E_a = 13,216 ± 242 cal mol^?1. This result gives rate constants that are about five times larger than those from previous studies. Although corrections for nonidealities in the reflected shock region are anticipated and under investigation, the expected changes will be relatively small and thus the large discrepancy noted here will remain.     

THE TIME-RESOLVED PHOTON-COUNTING FLUOROMETER AT THE NATIONAL SYNCHROTRON LIGHT.SOURCE

A single-photon-counting fluorometer, capable of steady-state and time-dependent measure-ments, is now operational at port U9B of the National Synchrotron Light Source at Brookhaven National Laboratory. Excitation wavelengths are selected by a prism-grating double monochromator. Emission energies are chosen by filter(s) or by a one-meter Spex monochromator. Commercial electronics are used for data acquisition, except for special circuitry required by the high (53 MHz) repetition rate of the synchrotron. A large sample chamber allows flexibility in arranging optical components and samples. The standard optical configuration of the sample chamber consists of a focusing mirror, a six position excitation optic wheel, a turntable with four thermostatted cuvette holders, a six position emission optic wheel, and an f/0.7 emission collection lens. Data acquisition and the setting of correct wavelengths and sample chamber optics are controlled by a Tektronix 4052 computer via the IEEE-488 General Purpose Interface Bus. Time-dependent fluorescence data are transferred to a VAX 11/730 for analysis; current deconvolution software includes nonlinear least-squares programs for single curve and global analysis.     

On the separation of geometric and viscoelastic dispersion in composite materials

With the completion of an experimental study of the dispersion characteristics of fiber-reinforced viscoelastic materials, a sufficient body of information has been generated to demonstrate the feasibility of separating viscoelastic dispersion from the total dispersion spectrum of this class of material. The basic procedure for the separation is to construct a homogeneous viscoelastic constitutive equation for the composite and to use cross plots of the viscoelastic characterization with the total dispersion spectrum of the composite to reveal the influence of viscoelastic dispersion on the total spectrum. Two methods of constructing the homogeneous model are discussed and the results are compared with experimental data.     

A SUGGESTIVE WAY OF DERIVING THE QUANTUM PROBABILITY RULE

The familiar modulus squared form of all quantum mechanical probabilities is derived from an assumption of equal a priori probabilities concerning the final states available.