A new method for extracting thermochemical values of surface and interface segregation in binary alloys from shifts in core-electron binding energies is applied to the case of Cu-Ni. The results for the heat of Cu surface segregation agree well with the calculated value. In addition to providing important thermochemical values this approach provides new insights into the relative importance of the different effects contributing to segregation phenomena.

Nonlinear mode-coupling hydrodynamics is used to study the broadening of spectral lines near a liquid-gas critical point. The critical contribution to the line shape is given by a universal line-shape function. For values of $\epsilon =\left|\frac{(T-T_c)}{T_c}\right|$ which are not too small, the line assumes a Lorentzian form and the width $\hat{\Gamma }$ increases as $\sim {\epsilon }^s$ with the critical exponent $s=\gamma +\nu =-0.607\mathrm{}$. Very close to the critical point the line changes into a Levy distribution [the Fourier transform of $\exp (-t^r)$ where $\mathcal{r}=\frac{(3-\eta )}{2}$] and the line shape becomes independent of $\epsilon$ ($s=0\mathrm{}$).

The behavior of the bend elastic constant above the nematic-to-smectic-$C$ transition in $\overline{7}\mathrm{S}5$ is found to follow the prediction of Chen and Lubensky. The nature of the director fluctuations in $\overline{7}\mathrm{S}5-\overline{8}\mathrm{S}5$ mixtures indicates that the nematic-to-smectic-$C$ transition near the nematic-smectic-$A$—smectic-$C$ multicritical point exhibits both smectic layer and tilt fluctuations and is not adequately described by existing models.

A large class of mean-field spin-glass models is solved by two methods. The first one uses an ergodicity hypothesis for the random variables which enter in the definition of the coupling constants. The second method is the well-known $n$-replicas trick. The comparison of these two methods when applied to a limit Hamiltonian of the class gives new insights on the Sherrington-Kirkpatrick model and on the breaking of the replicas' symmetry.

Electron energy-loss spectroscopy has been used to study the coverage-dependent, electronic excitations of Ar and Xe adsorbed on Al(111), Ag(111), Cu, and Au surfaces. The monolayer loss features and cross sections indicate broadened atomiclike excitations with no evidence for a configurational-switching effect suggested in previous optical studies. The $n{p}^5\mathrm{}(n+1\mathrm{})s$ excited-state lifetime is found to be ∼4 times longer than theoretically predicted for isolated adatoms.

A method is presented for calculating the core and valence spectra of a Ce compound in the impurity model at zero temperature. In the sudden limit this method becomes exact for large degeneracy of the $f$ level. In this limit the valence spectrum has an $f$ peak close to the Fermi energy, ${\epsilon }_{\mathrm{F}}$, even if the $f$ level is fairly far below ${\epsilon }_{\mathrm{F}}$, and usually there is a second $f$ peak at larger binding energy. These results correlate well with recent experiments for many Ce compounds. Both the core and valence spectra provide information about the occupancy of the $f$ level and about its coupling to the conduction band.

The local susceptibility of extremely dilute Ce ions recoil implanted into more than thirty metallic elements is microscopically observed by perturbed angular $\gamma$-ray distribution techniques. Many elements in which the single Ce ion reflects intermediate or even nonmagnetic behavior have been found. These results allow correlation of the magnetic Ce-ion behavior with matrix-dependent quantities.

The observation of cyclotron resonance in ${\mathrm{Cd}}_{0.9}$${\mathrm{Mn}}_{0.1}$Se implies the presence of free carriers at densities of 1.0×${10}^{14}$/${\mathrm{cm}}^3$. Transport and far-infrared data are shown to be consistent with a model in which there are $D^{-}$ levels in the sample under thermal-equilibrium conditions. It is argued that the $D^{-}$ levels result from fluctuations in the conduction-band edge due to random Mn concentration fluctuations. An activated dc conductivity also supports the model.

The large-scale anisotropy in the cosmic background radiation has been measured at 3-mm wavelength with a liquid-helium-cooled balloon-borne radiometer sensitive enough to detect the dipole in one gondola rotation (1 min). Statistical errors on the dipole and quadrupole components are below 0.1 mK with less than 0.1 mK galactic contribution. The authors find a dipole consistent with previous measurements but disagree with recent quadrupole reports. The measurement is also useful in the search for spectral distortions.

Observations with a high-sensitivity radiometer, covering 80% of the sky, give substantially improved measurements of anisotropy in the 2.7-K radiation. The dipole effect is $(T_x, T_y, T_z)=(-3.07\mathrm{}\pm 0.17, 0.67\pm 0.09, -0.45\mathrm{}\pm 0.09)$ mK; the Earth's orbital motion through the 2.7-K radiation is detected. No statistically significant quadrupole effect is seen, and a magnitude limit of 0.19 mK is established at the 90% confidence level. Covariance analysis for angular separations between 10° and 180° gives $〈\delta T_1\delta T_2〉<0.01\mathrm{}$ ${\mathrm{}\left(\mathrm{mK}\right)\mathrm{}}^2$.

A conjecture, based on a comparison of different mean-field-like approximations, is proposed for determining the first- or second-order character of phase transitions. The $q$-state Potts model and several gauge theories [$Z_2$, $\mathrm{U}\mathrm{}\left(N\right)\mathrm{}$, $\mathrm{SU}\mathrm{}\left(N\right)\mathrm{}$, SO(3)] on a lattice are considered. For $Z_2$ gauge theory, in particular, a critical dimensionality $d_c=3.66\mathrm{}$ is predicted, whereas for the Potts model $q_c=2.75\mathrm{}$ in $d=3\mathrm{}$, $q_c=2.4\mathrm{}$ in $d=4\mathrm{}$, and $q_c\propto \exp \left[\frac{1}{\mathrm{}(d-1\mathrm{})\mathrm{}}\right]$ for $d\to 1$ are obtained.

In the presence of a $\mathrm{CP}$ nonconservation measured by an angle $\theta$, the ground state of a point magnetic monopole is shown to have an electric charge of value $-\frac{e\theta }{2\pi }$ which changes discontinuously to zero for massless fermions. A new version of Levinson's theorm is also given. The latter effect as well as the $S$-wave helicity filp of a dyon can be interpreted as a leak at the origin.

The complete electromagnetic correction to a coordinate-space Feynman function is separated into a product of two factors. The first is a unitary operator that contains all contributions corresponding to the classical electromagnetic radiation field. The second is free of infrared divergences: It can be transformed into momentum space, and enjoys there the normal analytic properties. This result solves the infrared problem and maintains the physically correct asymptotic properties in coordinate space.

Excitation functions for complete fusion of ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$+${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ and ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$+${}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}$ have been found to decrease gradually over a broad energy range below the nominal barrier. The effective barrier for ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$+${}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}$ was 10.5 ± 3.0 MeV higher than the nominal barrier implying a critical effective fissility of 31.5 ± 0.5. Although deep-interpenetration processes appear to limit fusion at near-barrier energies, weak-contact dynamics enable these cold, heavy nuclei to fuse with comparative ease at lower energies.

Previous evidence from double beta decay (DBD) of ${}_{}{}^{128}{}_{}{}^{}\mathrm{Te}$ and ${}_{}{}^{130}{}_{}{}^{}\mathrm{Te}$ required neutrinoless DBD involving a neutrino rest mass of ${\hat{m}}_{\nu }\sim 34$ eV (∼10 eV in the most recent theoretical treatment) or else a strong violation of lepton-number conservation ($\eta \ne 0$) due to a ($V+A$) admixture. The DBD rate ratio of ${}_{}{}^{128}{}_{}{}^{}\mathrm{Te}$ and ${}_{}{}^{130}{}_{}{}^{}\mathrm{Te}$ has been redetermined. The present result is consistent with ${\hat{m}}_{\nu }=\eta =0\mathrm{}$. The experimental limits still allow Majorana decay at levels of ${\hat{m}}_{\nu }<~5.6$ eV or $\eta <~2.4\times {10}^{-5\mathrm{}}$ (95% confidence). The DBD half-life for ${}_{}{}^{128}{}_{}{}^{}\mathrm{Te}$ is $T_{\frac{1}{2}}\left({}_{}{}^{128}{}_{}{}^{}\mathrm{Te}\right)>\mathrm{}8\mathrm{}\times {10}^{24}$ yr ($2\sigma$).

Fast-fission phenomenon is apparent in time-dependent Hartree-Fock calculations of ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$+${}_{}{}^{74}{}_{}{}^{}\mathrm{Ge}$ collisions at $E_{\mathrm{lab}}\left(\mathrm{Pb}\right)=1600\mathrm{}$ MeV for a range of entrance-channel angular momenta between fusion and deep-inelastic processes. A long-lived composite system is formed which eventually leads to binary fragmentation with appreciable mass and charge drift and energy loss. The time scales are shorter than those for fusion, yet far too long compared to deep-inelastic processes. A cross section ${\sigma }_{\mathrm{ff}}=295\mathrm{}\pm 75$ mb is estimated.

The (${\pi }^{\pm }, {\pi }^0$) reactions were studied on targets of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ at 160 MeV by measuring the energy spectra of the neutral pions at several laboratory angles between 6° and 160°. The shapes of the energy spectra, the angular distributions, and the ratios of cross sections for isotopic pairs are used to infer the isospin dependence of the $\Delta$-nucleus interaction.

Water molecules are photolyzed by a ${\mathrm{F}}_2$ laser at 157 nm. The nascent OH (${}_{}{}^2{}_{}{}^{}\Pi _{\frac{3}{2}}^{}{}_{}{}^{}, v=0\mathrm{}$) rotational state distribution, probed via laser-induced fluorescence, reveals a strong preference for populating the upper $\Lambda$-doublet component. The population inversion is found to be a function of both the initial temperature of the ${\mathrm{H}}_2$O as well as the final rotational state in which the OH radical is formed. These results may provide a simple mechanism for the astronomical OH maser observed by others.

Self-consistent local-spin-density total-energy calculations for ${\mathrm{Cr}}_2$ and ${\mathrm{Mo}}_2$ yield ${{}_{}{}^1{}_{}{}^{}\Sigma _{\mathrm{g}}^{}{}_{}{}^{}}^{+}$ ground states with dissociation energies and equilibrium bond lengths in excellent agreement with experiment—in marked contrast with the results of a generalized-valence-bond-van der Waals approach, which used 26 512 determinants, and previous local-density efforts. The present results indicate the reliability of local spin-density theory for very inhomogenous systems, when sufficient variational (and symmetry) freedom is included.

The statistical behavior of complex atomic spectra of neutral and ionized rare-earth atoms has been examined. The authors found eight sets of atomic spectra of sufficient quality and statistics to compare with the predictions of random-matrix theory. Good agreement between theory and experiment was found for the covariance of adjacent spacings, $\mathrm{Cov}(S_i, S_{i+1\mathrm{}})$, and the ${\Delta }_3$ statistic.