The electronic and magnetic properties of a coherent modulated structure consisting of three atomic layers each of Cu and Ni perpendicular to [111] were determined from ab initio self-consistent spin-polarized energy-band calculations. We predict a substantial reduction in spin magnetization and contact hyperfine fields $H_n$ at the Ni layers (in contrast with enhancements reported earlier from ferromagnetic resonance measurements), charge (${0.1\mathit{e}}^{-}$) and spin (∼0.01${\mathrm{\mu }}_{\mathrm{B}}$) transfer to the Cu sites, and large $H_n$ at the Cu nuclei.

Surface $3d$ and $4d$ core-level binding-energy shifts have been resolved in photoemission from GaAs(110) and GaSb(110), which yield new information on semiconductor surface reconstruction. The shifts (∼0.3 eV) are toward higher (lower) binding energies for the surface cations (anions), in agreement with a simple model involving the known surface relaxation of GaAs(110) with a geometry-dependent initial-state charge transfer. Surface core-excitation binding energies, core-level widths, escape depths, etc., are reevaluated.

$2H$-Nb${\mathrm{Se}}_2$ undergoes a charge-density-wave (CDW) distortion at 33 K which induces $A$ and $E$ Raman-active phonon modes. These are joined in the superconducting state at 2 K by new $A$ and $E$ Raman modes close in energy to the BCS gap $2\Delta$. Magnetic fields suppress the intensity of the new modes and enhance that of the CDW-induced modes, thus providing evidence of coupling between the superconducting-gap excitations and the CDW.

If a superconductor has a Raman-active phonon mode of low frequency (larger but of the order of magnitude of the superconducting energy gap $2\Delta$, we show that electron-phonon coupling leads to a complex bound excitation, also Raman active, with a discrete frequency lower than $2\Delta$ and with intensity which can be appreciable. We propose that these are the lines found by Sooryakumar and Klein at approximately the energy-gap frequency in super-conducting $2H$-Nb${\mathrm{Se}}_2$.

For the first time crystal-field excitations are observed in the inelastic-neutron-scattering spectra of a mixed-valence system, viz., ${\mathrm{Ce}}_{0.9-x}{\mathrm{La}}_x{\mathrm{Th}}_{0.1}$. Scaling relationships are established which connect various energy-related quantities, such as the $T=0\mathrm{}$ Fermiliquid susceptibility, the valence transition temperature, and the spin-fluctuation energy as measured by the neutron scattering linewidths.

It is shown that the possibility of nonzero neutrino rest masses $m_{\nu }\approx 10$ ${\mathrm{e}\mathrm{V}/\mathit{c}}^2$ does not alter previous predictions of the standard big-bang model for the primordial ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ abundance. Although both left- and right-handed neutrinos could then be present, reactions mediated by the standard Weinberg-Salam-Glashow model extended to include Dirac neutrinos with nonzero rest mass cannot maintain ${\nu }_R$ in thermal equilibrium.

The critical behavior of the $O\left(n\right)\mathrm{}$ classical Heisenberg model in $d$ dimensions close to $n=d=2\mathrm{}$ is discussed, assuming analyticity in $n$ and $d$ of the renormalization-group equations. In the ($d$,$n$) plane there is a line passing through (2,2) across which the critical exponents are nonanalytic. For $d=2\mathrm{} \mathrm{and} -2\mathrm{}<~n<~2$, a conjecture is presented for the exact form of the leading and subdominant thermal eigenvalues.

The first four coefficients in the effective potential $V_{\mathrm{eff}}\left({\varphi }_R\right)=\Sigma {n=1\mathrm{}}^{\infty } V_{2n}{{\varphi }_R}^{2n}$ are calculated for a mass- and wave-function-renormalized $g{\varphi }^4$ field theory in $d$ space-time dimensions in the limit where the unrenormalized coupling $g\to \infty$ with the renormalized mass $M$ held fixed. The accuracy of these numerical results is verified by exact analytical calculations of the effective potential performed in 0 and 1 space-time dimensions.

It is shown that the Bogomolny equations for the simplest static, axially symmetric gauge fields are equivalent to the Ernst equation. The Bogolmolny-Prasad-Sommerfield one-monopole solution is obtained via Harrison's Bäcklund transformation.

Yields for specific $Z$ and $A$ have been measured for projectilelike fragments produced in the reaction of 8.3-MeV/u ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ ions with targets of ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$, and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$. Variances of the isobaric charge distributions ${{\sigma }_Z}^2\mathrm{}\left(A\right)\mathrm{}$ reveal a saturation value of ${{\sigma }_Z}^2\mathrm{}\left(A\right)\mathrm{}\approx 0.8$, reached within the first 30-50 MeV of energy loss depending on target. Variances of the isotopic mass distributions saturate at a value of ${{\sigma }_Z}^2\mathrm{}\left(A\right)\mathrm{}\approx 2-4$, which is reached after about 60-80 MeV of energy loss. The data are compared with $\frac{N}{Z}$ equilibration models.

The energy spectra of light particles ($p$,$d$,$t$) produced in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$-induced reactions on ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ at 315 MeV can be rather well described by thermal distributions in a rest frame that moves with about half the beam velocity. The energy spectra of deuterons and tritons can be related to the proton energy spectra by a coalescence model that incorporates Coulomb effects.

Differential cross sections are reported for ${\pi }^{+}$ + ${}_{}{}^{3,4}{}_{}{}^{}\mathrm{He}$ elastic scattering at 260, 295, and 310 MeV and ${\pi }^{-}$ + ${}_{}{}^{3,4}{}_{}{}^{}\mathrm{He}$ at 295 MeV. The angular distributions (except for ${\pi }^{-}$ + ${}_{}{}^3{}_{}{}^{}\mathrm{He}$) confirm the fixed angle ($\theta \approx 75°$) minimum seen at lower energies [caused by the (3,3) $\pi +N$ resonance dominance] and show a deep minimum at $\theta \approx 110°$. Comparisons are made to $\pi +d$ and the current discussion of pion excitation of intermediate dibaryon and $\Delta N$ states.

The value 0.026 49±0.000 43 is deduced for the deuteron asymptotic $D$- to $S$-state ratio from measurements of the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$($d$,$p$)${}_{}{}^{209}{}_{}{}^{}\mathrm{Pb}$ tensor analyzing powers at sub-Coulomb bombarding energies $E_d=7, 8, \mathrm{and} 9$ MeV. The quoted uncertainty includes statistical errors, beam-polarization measurement errors, and systematic errors which result from a choice of optical-model parameters used to describe the reaction. The result is compared to several theoretical deuteron wave functions.

The first relativistic calculation of elastic $\pi d$ scattering from threshold to ${T_{\pi }}^{\mathrm{lab}}=260\mathrm{}$ MeV is presented, based upon a completely coupled set of integral equations. The effects of intermediate pion absorption as well as scattering through the nonpole part of the $\pi N{P}_{11}$ partial wave are consistently included and found to be important. A reasonable agreement with experiments is encouraging for further detailed studies.

Microscopic calculations of the total reaction cross sections for protons on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, and neutrons on ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ have been made, which provide for the first time an excellent description of the data for projectile energies from 15 MeV through 1 GeV. The calculations are based on the experimental nucleon-nucleon total cross sections and explicitly include the effects of the real nuclear potential, the Coulomb potential, Pauli blocking, and Fermi motion.

The infrared ${\nu }_2$ band of ${\mathrm{H}}_3^{+}$ has been observed. A direct infrared absorption method combining a liquid-nitrogen-cooled multiple-reflection discharge cell and a difference-frequency laser system has been used for the detection. Fifteen absorption lines have been measured in the region of 2950-2450 ${\mathrm{cm}}^{-1\mathrm{}}$ and assigned. This is the first spectroscopic detection of this fundamental molecular ion in any spectral range.

The infrared vibrational-rotational spectrum of the ${\mathrm{D}}_3^{+}$ isotope of the simplest polyatomic molecule is observed. Eight intervals between 1750 and 1850 ${\mathrm{cm}}^{-1\mathrm{}}$ have been measured to an error of 0.0005 ${\mathrm{cm}}^{-1\mathrm{}}$ or 0.3 ppm (at 70% confidence level). Four have been identified as members of the fundamental degenerate vibrational band. The rest apparently involve unidentified higher vibrational-rotational levels.

The first few lines in the $P$, $Q$, and $R$ branches of the rotation-vibration spectra of the equilateral-triangle molecular ions ${\mathrm{H}}_3^{+}$ and ${\mathrm{D}}_3^{+}$, obtained by ab initio nonperturbative calculations, are reported. Comparison with observations indicates an accuracy better than 1% was obtained for both the infrared-active fundamental vibration frequency and the equilibrium internuclear distances.

Significant optical gain at 121.57 nm, the Lyman-$\alpha$ spectral line in inverted atomic hydrogen, was observed.

The asymmetry observed in intracavity resonances (especially of the Lamb-dip type) is attributed to a resonant nonlinear diffraction effect. Direct evidence of this effect is obtained by a new experiment and careful analysis of the diffracted light, in the geometrical shadow of the laser beam inside the cavity, which reveals a reversed asymmetry of the resonance. A modified Lamb-dip formula gives better agreement between experiment and theory. The effect occurs in many experiments with Gaussian beams, particularly in recent high-sensitivity intracavity laser spectroscopy.