Pressure effects on the semiconductor-semimetal transition in Ti2O3

Hydrostatic pressure has negligible effect on the resistivity anomaly and thec _H /a _H ratio of Ti₂O₃. The results are consistent with the band-crossing mechanism wherein the a ^T and e ^T bands cross as thec _H /a _H ratio increases.     

A new methodology for realizing magnification of holographic images

The article describes a new method for obtaining a holographic image of desired magnification, consistent with the stipulated criteria for its resolution and aberrations.     

Solid-state halide ion-selective electrodes: studies of quaternary ammonium halide solutions and determination of surfactants

The feasibility of using homogeneous membrane-type halide ion-selective electrodes in solutions containing cationic surfactant compounds was examined. The results established the applicability of these electrodes for monitoring halide ions in solution without interference by the surfactants. The data also provided a basis for estimation of the surfactant in solution through the halide content. Two typical plating-bath compositions containing CTAB have been successfully analysed for their surfactant content by this procedure.     

Spectrum of water vapor in the 1.9 and 2.7μ regions

The rotational structure of the ν₁, ν₃, 2ν₂, ν₁ + ν₂, and ν₂ + ν₃ bands of water vapor has been recorded using a high resolution vacuum infrared spectrograph. Values for the energy levels of the ground vibrational state and of the upper states of these bands have been determined. Several intensity anomalies have been observed in lines previously assigned to the ν₁, ν₃, and 2ν₂ bands. Experimental results for these intensity anomalies have been presented.     

Uniqueness of methyl fluoride force field

The uniqueness of the general harmonic force field of methyl fluoride is analyzed. The analysis is applicable to other methyl halides as well. Through the compliance scheme, it is seen that by supplementing the data employed by Aldous and Mills (i.e., vibrational frequencies ω_i, Coriolis coupling constants ζ_i and the centrifugal stretching constants D_J, D_JK of CH₃F and CD₃F molecules), with the frequencies of A′ or A″ species of either CH₂DF or CD₂HF, the force field is uniquely determined. The addition of any other extra data including the ¹²CH₃F¹³CH₃F isotopic shifts only makes the determination of the force field parameters more precise.     

High resolution spectrum and analysis of the ν2 band of 14N16O2

The ν₂ band of ¹⁴N¹⁶O₂ near 13.3 μm has been measured under high resolution using a vacuum grating spectrograph equipped with a liquid helium cooled Ge:Cu detector. Over 750 transitions were identified. Analysis of the band, combined with previous work at shorter wavelengths, led to modified constants for the ground state, (0, 0, 0), and new values for the constants of the upper state, (0, 1, 0). The new constants reproduced 272 nonzero-weighted transitions with a standard deviation of 0.011 cm^?1 and reproduced 346 ground state combination differences with a standard deviation of 0.010 cm^?1. The spin-rotation line splittings which were observed were described satisfactorily using existing formulations.     

Studies of mass and energy correlations in thermal neutron fission of U-235 accompanied by long range alpha particles

Several characteristics of fission accompanied by long range alpha particles (LRA) have been studied in the thermal neutron induced fission of²³⁵U. The kinetic energies of fission fragments and the LRA were measured with a back-to-back ionization chamber and semiconductor detectors respectively. The kinetic energies of the two fragments and the LRA in LRA fission, along with the energies of pair fragments in the normal binary fissions, were recorded event by event on a magnetic tape by means of a four-parameter data acquisition system. The data were analysed to study the dependence of different quantities in LRA fission on the fragment mass ratio, LRA energy and the total kinetic energy of the fission fragments. It is seen that the most probable energy of LRA increases significantly for near symmetric mass divisions. The total kinetic energy for all mass ratios in LRA fission is found to be (2.6±0.7) MeV larger than that in binary fission. The difference in the total kinetic energies in LRA and binary fissions is seen to be dependent on mass ratio. This result may suggest that the scission configuration in LRA fission is different for different mass ratios. Correlations between the fission fragment and LRA energies have been studied for several mass ratios. It is seen that the most probable fragment kinetic energyĒ _k varies nearly linearly with the LRA energyE _a for various mass divisions but the variation of the most probable LRA energyĒ _a with fragment kinetic energyE _k is found to deviate from linearity for several mass ratios. From a least square fit to the variation ofĒ _k withE _a it is found that the slope (dĒ _k/dE_a) increases with the increase in mass ratio. The present results are discussed to arrive at a better understanding of the scission configuration in the fission accompanied by LRA emission.     

Infrared bands of the HCNO molecule

Several vibration rotation bands of the H¹²C¹⁴N¹⁶O molecule have been studied by using high resolution vacuum grating infrared spectrographs. A linear molecular model has been used in establishing the vibrational assignments and evaluating the molecular constants. A value of 224.101 cm^?1 has been determined for the band center of the ν₅ fundamental by application of the Ritz combination principle. Future efforts will be directed to arriving at a similar result for the ν₄ fundamental.     

Phonon dispersion relations,effective interionic potential and liquid resistivity of Al

Phonon dispersion relations and effective interionic potential for solid Al are calculated using the nonlocal optimized model potential of Shaw screened with the improved self-consistent dielectric function of Vashishta and Singwi. A very good agreement is obtained between the calculated and experimental phonon frequencies. Comparison is made using three other dielectric functions. It turns out that in Al the interionic potential is very sensitive to the screening function. Also electrical resistivity of liquid Al has been calculated using the model potential when screened with the four different dielectric functions. Influence of the spatial distribution of depletion charge at the ion site is discussed. A comparative study of nonlocal and local potentials by taking two local potentials: (1) modified point-ion, and (2) empty core, screened with the self-consistent dielectric function, is also presented.