A new near infrared emission spectrum of (HeD)-He-4 has been recorded at 4.2 K during proton irradiation of a mixed sample of helium gas and solid deuterium. The upper state of the transitions is an admixture of the a...
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A new near infrared emission spectrum of (HeD)-He-4 has been recorded at 4.2 K during proton irradiation of a mixed sample of helium gas and solid deuterium. The upper state of the transitions is an admixture of the accidentally degenerate D(2)SIGMA+ (upsilon = 0) and C(2)SIGMA+ (upsilon = 3) levels. The lower state is the previously unobserved A(2)SIGMA+ (upsilon = 2) level. The observation of this levels allows for evaluation of the rotational constants B2" and D2" for the A(2)SIGMA+ state, and for a better estimate of the vibrational parameters omega(e)" and omega(e)"-CHI(e)".
Highly transparent conducting ZnO films have been deposited using ion-beam-assisted reactive vacuum deposition. The zinc deposition rate was controlled by adding gallium to the zinc in an open Al2O3 crucible source. O...
Highly transparent conducting ZnO films have been deposited using ion-beam-assisted reactive vacuum deposition. The zinc deposition rate was controlled by adding gallium to the zinc in an open Al2O3 crucible source. Oxygen was introduced into the system via a separate controlled leak and reacted with the zinc on the substrate. Mechanically stable polycrystalline conducting ZnO films having a preferred orientation were deposited with resistivities in the range from 4.0 x 10(-6) to 9.0 x 10(-6) OMEGA-m, with carrier densities of more than 2 x 10(26) m-3 and Hall mobilities between 2.8 X 10(-3) and 4.0 x 10(-3) m2 V-1 s-1. The average transmission exceeded 90% for films 350 nm thick in the wavelength range of the visible spectrum.
With the aid of molecular-dynamics technique, a calculation of the thermodynamic and structural properties of the crystallization of a supercooled metallic liquid is presented. The calculated results demonstrate a num...
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With the aid of molecular-dynamics technique, a calculation of the thermodynamic and structural properties of the crystallization of a supercooled metallic liquid is presented. The calculated results demonstrate a number of features of this crystallization. It now appears that the transition associated with this crystallization is a first-order-like phase transition in the Ehrenfest scheme.
The Raman and infrared spectra of cyanamide have been remeasured at lower temperatures (20 K) and higher laser powers (for the Raman). The recently obtained structure of cyanamide was used as a basis for calculations ...
The Raman and infrared spectra of cyanamide have been remeasured at lower temperatures (20 K) and higher laser powers (for the Raman). The recently obtained structure of cyanamide was used as a basis for calculations of the lattice dynamics. Standard models using atom-atom potentials of the exp - 6 form, an exponentially decaying attractive potential for the hydrogen bond and distributed dipoles on the atoms, gave good fits to the structural parameters and, with scaling, gave moderately good values for the lattice frequencies provided that it was assumed that the modes associated with librations about the long axis of the molecule were not observed.
An extended mean-field density-functional theory of the liquid-vapour interface of water is described. The theory generalizes standard mean-field theories of inhomogeneous molecular fluids by including quadratic order...
An extended mean-field density-functional theory of the liquid-vapour interface of water is described. The theory generalizes standard mean-field theories of inhomogeneous molecular fluids by including quadratic orders of the anisotropic component of the intermolecular pair potential in the free energy functional. The pair interaction is modelled by an isotropic plus point dipolar and quadrupolar potential. Analysis shows that dipole-quadrupole coupling terms in the potential are responsible for inducing spontaneous polarization at the liquid-vapour interface. The direction of the surface polarization is determined by the sign of the axial component of the molecular quadrupole tensor, as in the earlier phenomenological theory of Stillinger and Ben-Naim. Explicit calculations are performed using molecular interaction parameters given by the TIP4P potential model for water, employed in recent computer simulations of the water interface by Wilson, Pohorille and Pratt. The preferred molecular orientations at the interface predicted by the theory are analysed in detail and compared with previous simulation results.
We have developed a spectrally resolved confocal microscope with high photon efficiency for photoluminescence and fluorescence measurements. A scanning grating is placed inside the detection arm of the microscope so t...
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A new confocal scanning beam transmission and reflection microscope is described. The new microscope uses the same detector for both transmitted-light and reflected-light images. The transmitted beam is re-injected in...
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The development of smectic-A ordering at the interface between isotropic liquid and vapor is studied using a density-functional theory, based on a mean-field approximation for the effect of attractive pair interaction...
The development of smectic-A ordering at the interface between isotropic liquid and vapor is studied using a density-functional theory, based on a mean-field approximation for the effect of attractive pair interactions and weighted-density treatment of repulsive-core contributions. In contrast to earlier microscopic theories of this phenomenon, the bulk liquid and vapor phases are in complete coexistence with each other, and no arbitrary ‘‘surface fields’’ independent of molecular pair interactions are invoked. The wetting behavior of the interface is studied as a function of the molecular-core anisotropy, which controls the relative stability of bulk nematic and smectic-A phases, under conditions where the attractive pair interactions favor complete wetting by the nematic phase. There is a change to incomplete wetting by the smectic-A phase when the latter preempts the nematic, in a process analogous to a triple-point wetting transition. This is consistent with experimental results, but the growth of smectic layers at the interface is always found to be continuous, with no evidence of the first-order layering transitions observed in experiment.
The QED fermion self-energy and vertex functions are calculated for general values of the gauge parameter ξ with the unified-gauge formalism for axial-type gauges. The Ward identity is verified and the results are co...
The QED fermion self-energy and vertex functions are calculated for general values of the gauge parameter ξ with the unified-gauge formalism for axial-type gauges. The Ward identity is verified and the results are compared with the corresponding expressions in the Coulomb gauge and Feynman gauge.
In this paper, a two-dimensional model for water-oil-surfactant mixtures, previously studied by the Monte Carlo method, is now investigated by examining (4×∞) strips of the lattice using the transfer-matrix meth...
In this paper, a two-dimensional model for water-oil-surfactant mixtures, previously studied by the Monte Carlo method, is now investigated by examining (4×∞) strips of the lattice using the transfer-matrix method. The correlation and structure functions in the disordered phase are calculated accurately, as demonstrated by comparison with Monte Carlo results. We find the behavior of these functions to be similar to their counterparts on the more realistic three-dimensional lattice, justifying the use of two-dimensional lattices for studying the disordered phase. From these functions we calculated the disorder and Lifshitz lines which are used to divide the disordered phase into a region of ordinary fluid and a region of microemulsion. We also illustrate that two-dimensional models may not be able to produce the three-phase coexistence between microemulsion, the water-rich phase, and the oil-rich phase obtained with three-dimensional models.
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