## SEARCH

#### Institution

##### ( see all 22)

- Tata Institute of Fundamental Research 11 (%)
- Indian Institute of Science 6 (%)
- Bhabha Atomic Research Centre 3 (%)
- National Aeronautical Laboratory 3 (%)
- Agra College 2 (%)

#### Author

##### ( see all 83)

- Jha, Sudhanshu S 2 (%)
- Mande, Chintamani 2 (%)
- Verma, M P 2 (%)
- Acharya, P Kumara 1 (%)
- Agarwal, S K 1 (%)

## CURRENTLY DISPLAYING:

Most articles

Fewest articles

Showing 1 to 10 of 38 matching Articles
Results per page:

## The kinetic equation and the equation of momentum transfer for a plasma

### Pramana (1973-09-01) 1: 129-134 , September 01, 1973

An attempt is made to derive a simple form of the collision integral of the kinetic equation for a plasma, by using Rostoker’s equation which expresses the pair correlation function in terms of the distribution functions of the particles, and the conditional probability of one particle shielding the other. The conditional probability function is assumed to be given by its equilibrium value. By taking first order velocity-moment of the resulting kinetic equation, the equation of momentum transfer has been obtained.

## The effect of rotating fields in magnetic resonance

### Pramana (1973-10-01) 1: 165-171 , October 01, 1973

The phenomenon of magnetic resonance is studied by considering the transverse oscillatory field as superposition of two oppositely rotating fields. One of the rotating fields is taken as strong and the other relatively weak.

## Off-diagonal long-range order and currents in weakly coupled superconductors

### Pramana (1973-07-01) 1: 37-47 , July 01, 1973

Within the framework of quasi equilibrium approximation, Josephson’s expression for current in a weakly coupled superconducting system is derived without the use of any specific microscopic model. It is based only on the existence of the off-diagonal long-range order in the two-particle reduced density matrix. Allowing for deviations from the quasi equilibrium approximation, generalised Josephson equations are obtained which include ohmic terms. The effect of relaxation and thermal fluctuations is examined in detail to emphasise the physical origin of various terms in the expression for current.

## Shape-excited states of28Si

### Pramana (1973-12-01) 1: 269-273 , December 01, 1973

The Hartree-Fock (HF) minima for the nucleus^{28}Si were obtained for the prolate, oblate and spherical shapes using the interaction obtained by Preedom and Wildenthal. The interaction gives rise to large energy separation between the prolate and the oblate shapes. The spherical solution is just 2 MeV above the lowest HF (oblate) minimum. The spectrum projected from the oblate HF state is in good agreement with the experimental spectrum. The transition probabilities for the different energy levels also agree reasonably well. The configuration mixing calculations performed on the basis of states projected from the three shapes indicate that there is no significant mixing of different projected states. The second 0
_{2}^{+}
state, thus obtained, corresponds to the third 0
_{3}^{+}
state in the experimental spectrum and stems dominantly from the spherical HF state. It is seen that the structure of the energy levels of^{28}Si, especially the second 0
_{2}^{+}
level is very sensitive to the two body interaction. The results are compared with those obtained using the renormalised interaction of Kuo.

## The law of rectilinear diameter for the liquid-gas phase transition

### Pramana (1973-08-01) 1: 109-111 , August 01, 1973

A rigorous semi-microscopic derivation of the law of rectilinear diameter for the liquid-gas phase transition has been provided.

## A study of the variable moment of inertia models

### Pramana (1973-11-01) 1: 209-211 , November 01, 1973

The variable moment of inertia (VMI) model proposed by Holmberg and Lipas has been shown to be a special case of the VMI model of Mariscotti*et al.* The solution of Mariscotti’s model is expressed in terms of hypergeometric functions, which directly give the rotational energies or their expansions in terms of the quantity*F*(*F*+1), where*F* is the total angular momentum. The present way of looking at the VMI model also tells us how to write the general dependence of the vibrational energy and the moment of inertia on the energy*E*_{J}.

## Dynamics of H2O molecules in ferroelectric K4Fe(CN)6 · 3H2O

### Pramana (1973-09-01) 1: 161-164 , September 01, 1973

The infrared spectrum of potassium ferrocyanide trihydrate has been recorded both in the para and ferroelectric phases. From a combined study of the IR and Raman spectra, it is concluded that there are two sets of water molecules present in the lattice, one set being involved in stronger hydrogen bonding than the other. The ferroelectric transition appears to be associated with an ordering of the water dipoles.

## Local magnetic ordering of Fe impurities in Pd2MnSn

### Pramana (1973-07-01) 1: 53-60 , July 01, 1973

Mössbauer effect of Fe^{57} embedded as very dilute substitutional impurities in Pd_{2}MnSn was studied. The impurities are seen to replace the three elements in the alloy. Although the Curie temperature of the alloy is 189K, well below the room temperature, the Mössbauer spectrum recorded at room temperature consisted of two distinct 6-finger magnetic hyperfine spectra and a single unsplit line. One of the 6-finger patterns which corresponds to an internal magnetic field of*H*_{int}=−375 kOe is inferred to arise due to local magnetic coupling of the localized magnetic moments of Fe impurities at the Pd sites with those of the 4 Mn first nearest neighbours of the Fe impurities. The other 6-finger pattern which corresponds to an internal magnetic field of*H*_{int}=−335 kOe is inferred to arise due to the local magnetic coupling of the localized magnetic moments of the Fe impurities at the Sn sites with those of the 6 Mn second nearest neighboours of the Fe impurities. The difference in the internal magnetic fields observed at the Pd and Sn sites in the alloy could be understood qualitatively, on the basis of RKKY theory, as arising due to the different conduction electron polarization contributions to the net internal magnetic field at the Fe impurity sites. The results of the measurements suggest that the localized magnetic moments of Fe^{57} impurities at Pd and Sn sites are antiferromagnetically coupled with the moments of their neighbouring Mn atoms.

## Ferromagnetic behaviour of interacting superparamagnetic particle aggregates in basaltic rocks

### Pramana (1973-08-01) 1: 61-65 , August 01, 1973

Studies on two rare cases of magnetic behaviour in basaltic rocks are reported. In both the cases a peak in susceptibility occurs at −160°C. However, one sample shows only normal hysteresis loops at low temperatures in a wide range of fields, while the other sample shows a constricted hysteresis loop in 1000 Oe at −190°C. Both types of behaviour can occur as a result of differing states of aggregation of interacting superparamagnetic particles in the respective samples.