Electron-impact intramolecular vibrational and vibronic excitation of disordered multilayer ${\mathrm{O}}_2$ films is studied with primary energies varying from 2 to 20 eV. The intensity of the $v=1\mathrm{}$ to $v=4\mathrm{}$ vibrational modes of ground state ${\mathrm{O}}_2$ exhibits a broad resonance as a function of electron energy. At the resonance maximum the vibrational intensities are enhanced by one to two orders of magnitude. The resonance appears to be derived from gas-phase ${\mathrm{O}}_2$ quasibound states.

We have measured the intensity autocorrelation of light scattered from Pb${\mathrm{F}}_2$ in the temperature range 110 to 524°C. The observed relaxation times are too long to be caused by ${\mathrm{F}}^{-}$ diffusion. Alternative mechanisms are considered, including the diffusion of ${\mathrm{Pb}}^{++}$ or neutral lead. This is the first measurement of fluctuations in a superionic conductor by photon correlation spectroscopy.

Low density of random elastic scatterers provides a long-range correlation between transmitted and incident wave functions in any dimensionality. Exact formulas prove it. They also demonstrate different localization lengths for different quantities. The experimental implications are strong localization in very pure wires at reasonable temperatures and periodical resonance-type minima and maxima of a residual resistance in a static magnetic field. The results are also true for any (e.g., electromagnetic wave) random scattering.

The first measurement is reported of low-energy (20 meV) structure in the low-temperature dielectric function of two valence-fluctuation materials: Ce${\mathrm{Pd}}_3$ and Yb${\mathrm{Cu}}_2$${\mathrm{Si}}_2$. The structure is consistent with energy-dependent scattering of electrons off a resonant level whose width and position (relative to the Fermi level) are roughly comparable. No such structure is observed in the integral-valent materials Y${\mathrm{Pd}}_3$, Dy${\mathrm{Pd}}_3$, and Lu${\mathrm{Cu}}_2$${\mathrm{Si}}_2$. The valence-fluctuation compounds Ce${\mathrm{Cu}}_2$${\mathrm{Si}}_2$ and Ce${\mathrm{Al}}_3$ do not show a resonance above 4 meV.

A new relation is reported which quantitatively describes the fine structure of the chaotic region of period-doubling systems. The relation determines the onset of fundamental periods and of ergodic behavior. It involves bifurcation rates ${\gamma }_k$, which converge to a new universal constant $\gamma =2.948\mathrm{}05\dots$. This theory is in agreement with numerical determinations of ${\gamma }_k$.

An experiment gave results inconsistent with the simplest alternative to quantum gravity, the semiclassical Einstein equations. This evidence supports (but does not prove) the hypothesis that a consistent theory of gravity coupled to quantized matter should also have the gravitational field quantized.

Asymmetry in the hadron momentum distribution with respect to the lepton scattering plane for deep-inelastic neutrino and antineutrino scattering is calculated in the one-loop order in quantum chromodynamics. Observation of an asymmetry of a few percent with the expected sign should provide clean evidence for the existence of the three-gluon coupling.

A method is proposed to calculate quantum numbers on solitons in quantum field theory. The method is checked on previously known examples and, in a special model, by other methods. It is found, for example, that the fermion number on kinks in one dimension or on magnetic monopoles in three dimensions is, in general, a transcendental function of the coupling constant of the theories.

Measurements of the summed mass of projectile fragments, $M_s=\Sigma M_{\mathrm{pf}}$, are reported for 2.1-GeV/nucleon ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ + C and ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ + Mo. Unlike previous measurements of cross sections for individual projectile fragments, these measurements are quite sensitive to the size of the target nucleus. The distribution of summed residual projectile mass, $M_s$, provides the first conclusive evidence of the validity of the geometrical "abrasion" model of relativistic heavy-ion collisions.

Resonant photoemission spectra of Gd metal in the photon energy range of the $4d\to 4f$ excitation show previously unobserved $4f$ multiplet structures. These structures are identified as excited quintet lines by a comparison of a calculation in the fractional parentage scheme with the experimental curve, yielding excellent agreement. Our result provides new insight into the resonance interaction; it also implies an explanation of an unidentified resonance structure in SmS.

The energy dependence of the asymmetry in inelastic scattering of polarized electrons by Hg atoms (excitation of the $6{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$, $6{}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$, and $6{}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}$ states) has been studied for a scattering angle of 90° and collision energies between the threshold energies and 22 eV. Structures in the measured asymmetry have been found which are due to formation of negative-ion states. Evidence has been found that interference between exchange and fine-structure interaction also causes a scattering asymmetry.

Quantum chromodynamics may be broken to S${\mathrm{O}\left(3\right)\mathrm{}}^{\mathrm{g}}$ with S${\mathrm{U}\left(3\right)\mathrm{}}^{\mathrm{c}}$ triplets becoming S${\mathrm{O}\left(3\right)\mathrm{}}^{\mathrm{g}}$ triplets. If so, there could exist low-mass, fractionally charged diquark states that are not strongly bound to nuclei, but are rarely produced at present accelerator facilities. The breaking of quantum chromodynamics can be done with a ${27}^{\mathrm{c}}$, in which case this strong interaction theory is easily embedded in unified models such as those based on SU(5), SO(10), or E(6). Possible relevance of diquarks for fusion catalysis is described.

We apply a theory of hadronic final states based on the notion of elongated quark-antiquark structure to the multiparticle production in $e^{+}{e}^{-}$ annihilation. Our results compare very accurately with the available experimental information.

The relative cross sections for the $2N+\pi \to 2N$ reactions were determined where the initial two nucleons are in a relative $s$ state, and coupled either to isospin zero or to one. This information is extracted from two-nucleon coincidence measurements of the (${\pi }^{+}$, $2p$) and the (${\pi }^{-}$, $\mathrm{pn}$) reactions on targets of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$.

The nucleon exchange process in deep-inelastic collisions is investigated by studying the one-way current constructed using the Wigner transform of the time-dependent Hartree-Fock one-body density matrix. Detailed calculations for head-on ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ collisions at three different bombarding energies have been performed. A combination of two simple models for the contributions from relative motion and tunneling is shown to predict one-way currents close to the time-dependent Hartree-Fock results.

From work on the $2S-2P_{\frac{1}{2}}$ transition of atomic ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, perturbed by noble gases, and use of the photon-echo technique, the first measurement of a "total" atomic-radiator-perturber scattering cross section is reported. The phase-changing, inelastic, and velocity-changing aspects of collisions contribute to this cross section, which is significantly larger than the corresponding pressure-broadening cross section. Typical velocity changes are found to be roughly one percent of the mean thermal speed.

We report an experimental observation of intramolecular electron-spin relaxation in isolated, collision-free molecules, in a molecular-beam apparatus. The relaxation was probed by a Stern-Gerlach experiment with Rabi-type inhomogeneous magnets. Relaxation was found to be very efficient for molecules such as chromium acetylacetonate and U${\mathrm{Cl}}_4$. For the nitroxide free radical TEMPO (2,2,6,6-tetramethylpiperidinooxy) relaxation times of about 0.4 and 200 μs were found in effusive and supersonic beams, respectively.

The predictions of the nonlinear Schrödinger equation have been tested by passing 5.5-psec optical pulses through a 70-m single-mode optical fiber. With use of a precise cross correlation technique based on pulse compression, dramatic reshaping of the input pulses into flat-topped, frequency-broadened, and positively chirped 20-psec output pulses with self-steepened fall times of less than 2 psec was observed. The observations are in good agreement with theory.

Observations of light backscattered from air bubbles in a viscous liquid demonstrate an enhancement due to axial focusing. A physical-optics approximation for the cross-polarized scattering correctly describes the spacing of regular features observed. The non-cross polarized scattering is not adequately described by a single class of rays.

Representing a large heat flow in a plasma as a flow of hot relatively collisionless electrons balanced by an opposing current of cold collisional electrons, it can be shown that an electrothermal instability can be induced in the cold resistive plasma when the heat flow exceeds about 3% of the free-streaming limit. This is nonconvective if the temperature of the cold plasma is less than $0.2{n_e}^{\frac{1}{4}}{Z}^{\frac{1}{2}}$°K, with $n_e$ in ${\mathrm{m}}^{-3\mathrm{}}$. The instability will lead to filamentary magentic structures with a typical growth time of a few picoseconds and wavelength about 10 μm.