Single and double $K$-vacancy fractions have been extracted from measured charge-state distributions (CSD) for F ions moving in solid C in the velocity range $4<~\frac{v}{v_0}<~9$. The CSD's are analyzed in terms of separate $K$-shell and $L$-shell distributions. The importance of the shifts in the $L$-shell distribution for 0, 1, or 2 $K$ electrons is demonstrated. The results are consistent with previous x-ray results, measured in the velocity range $2<~\frac{v}{v_0}<~9$.

Radiative lifetimes of 22 levels in Rh I and of 35 levels in Ta I are reported. The lifetimes are measured with the use of time-resolved laser-induced fluorescence on an atomic beam. The Rh I lifetimes resolve the discrepancy between the spectroscopically determined solar abundance of Rh and the abundance of Rh determined from chondritic meteorites.

The lowest septests of ${\mathrm{B}}^{-}$ associated with configurations $1s2s2p^{2}3s3p$ and $1s2s2p^{2}3p^2$ have been explored, including the effects of electron correlation, and one new bound state, the ${}_{}{}^7{}_{}{}^{}S$, having an affinity of 0.0857 eV, has been found. As the state decays primarily by radiative autoionization, it may be a candidate for lasing activity.

We present a quantum version of the classical phenomenological concept of viscosity different from those given by Feshbach and Tikochinski and by Ghosh and Hasse. It is also based on the method of dual coordinates, and we show that the problems which arise from quantizing the bilinear Hamiltonian due to the unphysical nature of one of the degrees of freedom can be circumvented. The idea is to extract from the method the correct dynamics for the physical degree of freedom only. Demanding the correct quantum behavior for this degree of freedom in the frictionless limit specifies to a large extent the role played by the unphysical degree of freedom and leads to very reasonable results also for the classical limit of the free particle subject to a linear viscous force.

Addition of the external noise allows one to select a unique invariant distribution which characterizes attractors of a one-dimensional map. Expressions for the Fourier transform of this distribution and the Liapunov exponent are derived. We find that in the presence of noise dynamical averaging, performed numerically, and statistical averaging, performed with the invariant distribution, are the same.

We describe a new technique which utilizes two beams of electrons to study the electron scattering from the excited states of atoms and molecules. The capability of the technique is specifically demonstrated by applying it to the process of dissociative electron attachment with vibrationally excited C${\mathrm{O}}_2$.

Relativistic computations of $K$-$\mathrm{MM}$ Auger spectra have been carried out in the intermediate-coupling scheme with configuration interaction. Good agreement with the scarce experimental data is attained. The calculated $K$-$M_1{M}_{4,5}$ intensity is found to peak sharply in the neighborhood of $Z=63\mathrm{}$. This peculiar behavior is traced to the crossings of two-$M$-hole energy levels, as functions of atomic number.

We present experimental data showing the first observation of large enhancement of four-wave mixing signals due to velocity-changing collisions. The results are explained with a simple model which describes the population distributions in the presence of velocity-changing collisions and optical pumping, allowing relative velocity-changing collision rates to be inferred from the data.

We have shown, using Monte Carlo stimulations, that long-range order exists in the nematic liquid-crystal phase in two dimensions when realistic interparticle potentials are used.

We studied a sequence of transitions between wavy-vortex-flow states with $m=3\mathrm{}$, in which a vortex pair was gained or lost. We found that the local-vortex pair width $\lambda$ became nonuniform as the Reynolds number was increased. Transitions occurred when the local $\lambda$ was larger (smaller) near the center (ends) than the stability limit for the underlying Taylor vortex flow, extrapolated into the wavy-vortex-flow regime.

We introduce a thermodynamic model of equilibrium polymerization capable of treating all physically important effects: monomer activation, growth of linear polymers, growth of ring polymers, excluded volume, (bi)functionality, polymer rigidity, and the effects of solution. We predict a possibility of both ordering and nonordering polymerization and a possibility of "reentrant" polymerization. The model may be used as a vehicle for studying liquid-crystal polymers.

It is observed that the Navier-Stokes rescaling invariance $\overrightarrow{\mathrm{x}}\to \lambda \overrightarrow{\mathrm{x}}$, $t\to {\lambda }^{2}t$, $\overrightarrow{\mathrm{v}}\to {\lambda }^{-1\mathrm{}}\overrightarrow{\mathrm{v}}$ shows up in the chemotaxis of motile $E$. coli and the phototaxis of $P$. uncinatum. Quantitatively accurate measurements on other motile bacteria and blue-green algae may reveal that this underlying hydrodynamic symmetry is featured commonly in the tactic migration of micrometer-size organisms in aqueous media.

Magnetically induced birefringence measurements were performed in the isotropic phase of methoxybenzylidene butylaniline (MBBA). Over the entire temperature range studied, $\Delta n$ was found to be linear in $H^2$ to fields over 10 T. This result is consistent with the Landau model of the nematic-isotropic transition, and strongly inconsistent with the results of Keyes and Shane [Phys. Rev. Lett. 42, 722 (1979)] in a similar experiment. Their results indicate both the approach of a field-induced critical point and tricritical behavior near the phase transition.

We present dynamic equations for the slow macroscopic variables of the wavy vortex state. The static solutions explain in a qualitative way recent experimental results of Ahlers et al. on the variation of the vortex diameter throughout the cell. In addition, we predict the existence of a pair of propagating or overdamped normal modes (depending on the wave vector of the disturbance) formed by the slow variables.

We have determined the Reynolds number versus axial wavelength stability curve for a six-wave state in the range $1.4R_c<R<\mathrm{}8\mathrm{}{R}_c$, where $R_c$ corresponds to the onset of Taylor vortex flow. At points well within the region bounded by the stability curve, the entire flow pattern has an axial periodicity and a sixfold rotational symmetry, even for fluid height-to-gap ratios as large as 290. However, when a stability boundary is approached, irregularities in the flow pattern appear; then when the stability boundary is reached, there is a change in the number of waves or the number of vortices or both.

It is shown that viscosity and thermal conductivity leads to large-scale steady convection in a cylindrical current-carrying plasma, under the influence of a magnetic field satisfying $\left(\frac{B_{\theta }}{B_z}\right)>>1\mathrm{}$. This state is the analog in a plasma of stationary convection in ordinary hydrodynamics.

We report experimental results on the spatial distribution of soft-x-ray bremsstrahlung emission in dense layers of laser-produced plasma. Density and temperature gradients in the thermal transport region, between the ablation surface and the critical density layer, are discussed by comparing calculated and observed bremsstrahlung radiation for various laser parameters. In particular, it is found that the temperature gradient length is several times longer for 1.06- than for 0.153-μm laser wavelength.