Analysis of the relationship between temperature dependence of the libration mode and dielectric relaxation in NaNO2

The behavior of the low frequency dielectric constant of NaNO₂ as function of frequency and temperature is consistently correlated to the temperature behavior of the frequencies and linewidths of the phonons of B₁ symmetry in the crystal. The frequency of the librational ‘soft’ mode closely related to the ferroelectric-paraelectric phase transition does not go to zero but tends to a hard core value at the transition temperature. The behavior of the dielectric constant as function of temperature and frequency is explained by assuming a dielectric relaxation mechanism proposed by Mason and not by Cochran's soft phonon model.     

Phonon bands in a π-electron charge-transfer complex

Phonon bands in mixed-stack π-electron charge-transfer complexes are investigated using Raman spectroscopy. Specifically, the Raman phonon spectra of naphthalene: antimony trichloride system is discussed in detail. The effect of the substitution of the donor and the acceptor is used to examine relative amplitudes of various motions on the donor and the acceptor. Phonon delocalization is investigated using various mixed crystals containing donor and acceptor impurities. The result obtained is discussed in terms of two models: (i) the giant molecule model, and (ii) the sublattice model.     

Matthiessen's rule and its variation for cyclotron resonance width in two and three dimensions

Based on the proper connected diagram expansion, we calculated cyclotron resonance widths Γ_n associated with neighboring Landau states (n, n +1) for free electrons in interaction with more than one kind of impurities. In 3D usual Matthiessen's rule Γ_n=Γ⁽¹⁾_n+Γ⁽²⁾_n+…where Γ⁽ⁱ⁾_n represent widths calculated separately for each kind, is obtained. In 2D a new rule: is obtained.     

Modulation instability of whistler waves

The Karpman and Krushkal criterion has been applied to nonlinear Schrödinger equation derived for whistler waves propagating through magnetoplasma containing parallel electrostatic field. The role of parallel electrostatic field on the frequency spectrum and growth rate of modulational instability has been discussed.     

Spectroscopic studies of the decay of hydrogen plasmas in aT-tube

This paper reports on spectroscopic studies of the decay of hydrogen plasmas generated in a relatively low energyT-tube of conventional design equipped with a reflector. These measurements indicate that the plasma behind the reflected front is not quiescent, but suffers a severe expansion with flow velocities ～10⁵ cm s^?1 (velocities of the incident and the reflected front are 7×10⁶ and 3.4×10⁶ cm s^?1). The net energy loss during the first two microseconds of the decay is almost entirely due to radiative losses (principally Ly-α radiation) and no significant radial temperature gradients are observed.     

Molecular interaction and other thermodynamic properties in ternary liquid mixtures

Molecular interaction, adiabatic compressibility, intermolecular free length, molar volume, available volume and free volume have been computed by measuring ultrasonic velocity and density at 23°C in three ternary liquid mixtures with p-xylene as common component. The systems are I p-xylene-acetone-carbon tetrachloride, II p-xylene-acetone-cyclohexane and III p-xylene-benzene-cyclohexane. Molecular interaction is maximum when the mole fraction of acetone is 0.5 in I and 0.6 in II. It remains almost constant in III indicating no interaction in this case. The excess properties have also been given and the interactions explained.     

Union congruence in a subspace of a Finsler space

Summary The union curves of a Riemannian space were studied bySpringer [8],Misra [2] andUpadhyay [9]. In a Finsler space, these curves have been studied byPrakash-Behari [4],Sinha [7],Mishra-Sinha [3] andSingh [6]. In the present paper, we wish to extend the concept of union curves in the Finsler space and as such the concept of union congruence has been discussed. The two types of union curves of the Finsler subspace are the particular cases of these curves. These are also generalization of union curves and union curvatures of a vector-field of Finsler space. It has also been shown that the λ-geodesics [5] are special case of these curves. Entrata in Redazione il 14 settembre 1970.     

Anomalous permeability in Polder-Smit region of ferrites

A study of the magneto-microwave Kerr effect on two samples of ferrites lying in the Polder-Smit region gives a negative value of μ', the real part of the transverse diagonal term of permeability tensor. There is a negative peak for μ' at a d.c. magnetization approximately equal to $\text{3}\text{4}$ of the saturation magnetization.