Proceedings of the Indian Academy of Sciences - Section A

Jayaraman, A.

doi: 10.1007/BF03047045pmid: N/A

The communication reports the results of study of the luminescence spectra of diamonds recorded at liquid-air temperature (80° K.). Apart from the two well-known electronic frequencies at λ 4152 and λ 5034 and the associated band systems, the present study has revealed the existence of three new electronic emissions centred at λ 4958, λ 5106 and λ 5786 which come out with great intensity along with the vibrational bands excited by them. Numerous sharp electronic lines also appear in the spectrum of some of the diamonds.

Ramaiah, N.; Chaturvedi, R.

doi: 10.1007/BF03047046pmid: N/A

Conductance measurements of murexide or ammonium purpurate solutions were made at 30° + 0.05°C. using a Serfass conductivity bridge. Ostwald’s dilution law was found to be inapplicable; equivalent conductance at infinite dilution and the classical and thermodynamic dissociation constants were computed by various methods applicable for systems involving ion association. The following physico-chemical constants of murexide were calculated :- (a) Thermodynamic dissociation constant. (b) Ionic mobility of purpurate ion. (c) Ionic rasius. (d) Diffusion coefficient.

Prakash, Nirmala; Behari, Ram

doi: 10.1007/BF03047047pmid: N/A

In the present paper the deviations from parallelism and equidistance are studied for Finsler spaces in Cartan’s sense and for Finsler space which is locally Minkowskian. By considering an orthogonal ennuple of hypersurfaces in Fn properties of associate curvature or angular spread vector have been studied.

Ramakrishnan, Alladi; Radha, T.; Thunga, R.

doi: 10.1007/BF03047048pmid: N/A

The Feynman propagator, in momentum representation, is a four-dimensional transform over space and time variables. If the space and time integrations are performed separately, the propagator can be decomposed into two parts, one corresponding to positive and the other to negative energy intermediate state. By the use of this decomposed propagator, the relative contributions of the positive and negative energy intermediate states to the matrix element can be estimated. For example in Compton scattering it leads to the apparently paradoxical result that in the “nonrelativistic approximation” it is only the negative energy intermediate state that contributes to the matrix element.

Ramachandran, G.

doi: 10.1007/BF03047049pmid: N/A

The paper deals with the theory of the diffraction pattern of helical structures having the number of units per turn (n) neither integral nor rational. The conventional treatment suffers from the defect that the repeat spacing along the axis of the helix is taken as the standard of reference, and this does not exist, being infinite, whenn is irrational. The difficulty is got over in this paper by focussing attention on the ‘unit height’ (h = resolved component of a unit along the axis) and ‘unit twist’ (t = fraction of a complete rotation for one unit, = l/n), which vary continuously irrespective ofn being rational or irrational. Explicit formulæ are obtained in terms of their Bessel indices for the observed layer line-spacings which turn out to be very simply related to the reciprocals of the unit height and the pitch of the helix, A technique of analysing, the observed diffraction pattern for the elements of the helical structure is also given, with examples. The case of a coiled-coil is seen to have the same general features as the simple coil, the layer line-spacing being now related to two pitches, namely, those of the major and the minor helices, and the unit height. The relationship of the diffraction pattern of a helix in its uncoiled and its coiled-coil form is also found to be rather simple, being similar to the multiplet splitting produced by a magnetic field in spectral lines.