R K Asundi
Articles written in Proceedings – Section A
Volume 1 Issue 8 February 1935 pp 542-554
Volume 1 Issue 11 May 1935 pp 830-840
Volume 2 Issue 1 July 1935 pp 30-45
Volume 3 Issue 1 January 1936 pp 346-359
Volume 3 Issue 4 April 1936 pp 346-359
Volume 3 Issue 5 May 1936 pp 466-481
Electronic configuration and bond energy
The original interpretation of the method of molecular orbitals as a theory of valency, in which the single electron possesses bonding power was based on the assumption that non-premoted electrons are bonding and premoted ones are anti-bonding or non-bonding. This assumption is not the outcome of any requirements of theory but is an empirical postulate, which seeks justification in experimental facts. Earlier attempts at correlation between the electronic levels of molecules and the energy states of the constituent atoms indeed appeared to lend support to this assumption. Later investigations have, however, shown that completely different correlations are possible and are absolutely necessary to satisfy the experimental facts. For example, in a molecule like BeO the stable triplet term, which should arise from unexcited atoms according to the older correlation, is not found and by the correlation of certain excited terms to anomalous terms of the metal atom it is shown, that a non-premoted odd electron in the configuration of the ground level lowers its dissociation energy. Similar remarks apply to the types BeF and NO and the new correlation of molecular terms to atomic states from the pair-bond view is shown to be satisfactory without exception in a larger number of molecules of these three classes, recently.
These three types represent molecules with free valencies and indeed just in such molecules the difference of the two view-points must become apparent. For other such molecules with free valencies, whose band spectrum is investigated in detail,
Volume 3 Issue 6 June 1936 pp 554-561
Rotational analysis of the ÅngstrÖm bands at λλ 6080 and 6620 Å.u.
Volume 3 Issue 6 June 1936 pp 562-565
Volume 5 Issue 3 March 1937 pp 235-243
Some remarks on the birge-sponer method of vibrational extrapolation
Volume 5 Issue 3 March 1937 pp 244-248
Note on the structure of N2+ and its bearing on the theory of valency
Volume 6 Issue 3 September 1937 pp 207-228
Volume 6 Issue 5 November 1937 pp 281-286
Volume 6 Issue 6 December 1937 pp 328-332
Volume 12 Issue 5 November 1940 pp 491-493
New bands in the triplet carbon system
A few new band heads belonging to the triplet carbon band system of CO are reported. These necessitate an increase of two units in the existing
Volume 12 Issue 6 December 1940 pp 513-518
R K Asundi S Mujtaba Karim R Samuel
From the experimental conditions under which the spectra are obtained it is assumed that they are due to molecular radiation. Thermochemical and spectrascopic data enable one to illustrate the relation among the energy levels of the various systems in the formation of the multi-atomic molecules from their constituent atoms. Such simplified Franck-Condon diagrams are constructed for SnCl4 (which includes SnCl2) and SiCl4. An interpretation, uniform in all cases, of the observed continuous bands in terms of the transitions among the energy levels, transitions, which of course involve a repulsive state for their final level, is suggested.
Volume 18 Issue 1 July 1943 pp 8-10
Spectral and collision data of CO+ and the dissociation energy of carbon monoxide
Volume 22 Issue 2 August 1945 pp 60-66
A discharge tube containing air at low pressure is excited by h.f. frequency oscillations from a modified Hartley circuit. It is observed that there is a critical frequency of exciting oscillations, namely 735 k.c.|sec. below which the colour of the discharge is pinkish red and above which the colour is orange yellow. The spectrum of the discharge in the visible region consists of the first positive and second positive bands of nitrogen. A study of some of these bands as regards their intensity variation depending upon the frequency of exciting oscillations is made. It is found that the first positive bands at 5371, 5406 and 5441 Å decrease in intensity as the frequency of exciting oscillations is reduced from 790 to 680 k.c.|sec. The second positive bands at 4355, 4417, 4490, 4649, 4724, 4815 and 4917 Å on the other hand, increase in intensity under the same conditions. The results are in harmony with the theoretical conceptions, regarding such phenomena and allow us to conclude that in the present experiments an energy of 15 e.v. is available for excitation when oscillations of frequency 735 k.c.|sec. are used.
Volume 22 Issue 3 September 1945 pp 1- Erratum
Volume 55 Issue 2 February 1962 pp 106-112
The1I6 state of Pr3+ in LaCl3 at 77°K
R M Agrawal R K Asundi R C Naik D Ramakrishnan Shobha Singh
A single crystal of 5% Pr3+ in LaCl3 was grown by Stockbarger’s method and its absorption spectrum at 77° K. recorded in the region 4200–5400 Å on a grating spectrograph having a dispersion of 5 Å/mm. in the first order. Polarization of the absorption lines has also been obtained. In the group of lines arising from1I6 ←3H4 transition, six more lines in addition to the four previously known have been observed. Satisfactory analysis of all these ten lines is given. One additional Stark level in1I6 is established at 21407 cm.−1 with
Volume 55 Issue 6 June 1962 pp 325-329
Ultra-violet absorption spectra and higher excited states of Nd3+ in LaCl3 at 77° K.
R M Agrawal R K Asundi R C Naik D Ramakrishnan Shobha Singh
The paper deals with an extension towards shorter wavelengths of the absorption spectrum of Nd3+ employing a 5% Nd3+ doped LaCl3 crystal. Five new groups of lines have been recorded and the analysis and interpretation of one of these groups,
Volume 73 Issue 5 May 1971 pp 240-249
Absorption and fluorescence spectra of praseodymium in KCl and KBr matrices
R K Asundi R C Naik P Ramakoteswara Rao
The observed fluorescence and absorption spectra of single crystals of KCl and KBr doped with praseodymium (Pr) show that the rare earth enters substitutionally as Pr3+ in these lattices. However, the site symmetry of the ion has at most a twofold axis. This is shown by the fact that the
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