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PublicationArticle Spectroscopic studies on complexes of magnesium (II) with C2-chiral bis-oxazolines(Elsevier, 1997) R.P. SinghThe configurations of chloro, ethyl and bis-complexes of magnesium with C2-chiral bis-oxazolines such as 2,2′-methylenebis[(4S)-4-iso-propyl-2-oxazoline] (MBIO). 2,2′-methylenebis[(4S)-4-tert-butyl-2-oxazoline] (MBTO) and 2,2′-methylenebis[(4S)-4-phenyl-2-oxazoline] (MBPO) have been investigated on the basis of spectroscopic studies. The IR and NMR (1H, 13C) data suggested that the bis-oxazoline ligands coordinated magnesium (II) through both the nitrogen atoms. The molecular weight determination in nitrobenzene indicated the dimeric nature of chloro and ethylmagnesium complexes whereas bis-magnesium complexes were found to be monomeric. © 1997 Elsevier Science B.V.PublicationArticle Synthesis and structural studies of some first row transition metal complexes of salicylaldehyde hydrazone(1979) R.C. Aggarwal; N.K. Singh; R.P. Singh[No abstract available]PublicationArticle Magnetospheric electron temperatures inferred from whistler observations at low latitudes(2008) Krishna K. Singh; A.K. Singh; M. Altaf; M.M. Ahmad; B.L. Koul; Lalmani; R.P. Singh; Jaipal Singh; Balraj KumarWhistler observations during night times made at low latitude Indian ground stations Jammu (geomag.lat.22° 26'N; L= 1.17), Nainital(geomag.lat., 19° 1' N; L= 1.16) and Varanasi (geomag.lat., 14°55'N; L = 1.11) are used to deduced electron temperatures in the vicinity of the magnetospheric equator. The accurate curve fitting and parameter estimation technique are used to compute nose frequency and equatorial electron densities from the dispersion measurements of short whistlers recorded at Jammu, Nainital and Varanasi. These computed parameters are further used to estimate the magnetospheric electron temperatures from the dispersion analysis of short whistlers observed at low latitudes which are in good agreement with the results reported by other workers. © 2008 IACS.PublicationArticle Study of physiological potentiality of callus and plant regeneration through somatic embryogenesis in rice variety swarna(2011) Sananda Mondal; R.P. Singh; Chaitali Sen; Bandana BoseThe regeneration protocol was developed from dehusked and sterilized seeds of rice variety Swarna (MTU 7029) to study callus induction, callus growth rate and regeneration potentiality. Different ranges of 2,4-D (1-4 mg L -1) and combinations of 6-Benzyl Aminopurine (BAP) (2-4 mg L -1) and a-Naphthalene Acetic Acid (NAA) (1 mg L -1) were used for callus induction, somatic embryo formation and plantlets regeneration respectively. Ninty six percent callus induction efficacy was found with 4 mg L -1 2,4-D. Whereas the high frequency of plantlets regenerated from embryogenic calli were observed in the combination of 4 mg L -1 BAP and 1 mg L -1 NAA; the embryogenic calli obtained from 2 mg L _1 2,4-D concentration performed better in this media (4 mg L -1 BAP and 1 mg L -1 NAA) than the other three used concentrations of 2,4-D. Physiological potentiality of 45 days old calli in terms of fresh and dry weights and proline content were showed a positive correlation. However, 4 mg L -1 2,4-D in medium showed low regeneration capacity of calli. © 2011 Academic Journals Inc.PublicationArticle Evolution of collectivity and shape transition in Zn 66(American Physical Society, 2020) S. Rai; U.S. Ghosh; B. Mukherjee; A. Biswas; A.K. Mondal; K. Mandal; A. Chakraborty; S. Chakraborty; G. Mukherjee; A. Sharma; I. Bala; S. Muralithar; R.P. SinghExcited states in Zn66 were investigated through the in-beam ?-ray spectroscopic techniques using the Cr52(O18, 2p2n) fusion-evaporation reaction at a beam energy of 72.5 MeV. The ?-rays emitted by the de-exciting nuclei were recorded in coincidence mode using the 14 Compton suppressed Ge clover detectors of the Indian National Gamma Array. With 14 new transitions being identified, the level scheme of Zn66 has been extended up to the excitation energy ˜12.3MeV and spin ˜17?. A rotational band, associated with the two quasineutrons from the 1g9/2 orbital, has been found to exhibit a band crossing with the ground-state band at a spin of 6?. The evolution of the collectivity and shape transition in this nucleus have been discussed in the framework of the total Routhian surface calculations and in comparison with the neighboring Ge68,70 nuclei. © 2020 American Physical Society.PublicationArticle Self-focusing of whistlers(1981) I.M.L. Das; R.P. SinghExpressions for the critical power for self-focusing, the self-focusing distance and the transverse dimension of the region of the developed instability have been derived for obliquely propagating whistler waves. These expressions have been used to estimate the various self-focusing parameters for ionospheric as well as magnetospheric propagation. © 1981.PublicationArticle Lifetime measurements in shape transition nucleus 188Pt(Springer New York LLC, 2017) Aman Rohilla; C.K. Gupta; R.P. Singh; S. Muralithar; S. Chakraborty; H.P. Sharma; A. Kumar; I.M. Govil; D.C. Biswas; S.K. ChamoliNuclear level lifetimes of high spin states in yrast and non-yrast bands of 188Pt nucleus have been measured using recoil distance plunger setup present at IUAC, Delhi. In the experiment nuclear states of interest were populated via 174Yb(18O,4n)188Pt reaction at a beam energy of 79MeV provided by 15 UD Pelletron accelerator. The extracted B(E2 ↓) values show an initial rise up to 4 + state and then a nearly constant behavior with spin along yrast band, indicating change of nuclear structure in 188Pt at low spins. The good agreement between experimental and TPSM model B(E2 ↓) values up to 4 + state suggests an increase in axial deformation of the nucleus. The average absolute β2= 0. 20 (3) obtained from measured B(E2 ↓) values matches well the values predicted by CHFB and IBM calculations for oblate (β2∼ - 0. 19) and prolate (β2∼ 0. 22) shapes. As the lifetime measurements do not yield the sign of β2, no definite conclusion can be drawn on the prolate or oblate collectivity of 188Pt on the basis of present measurements. © 2017, SIF, Springer-Verlag Berlin Heidelberg.PublicationArticle Features of discrete VLF emissions observed at Gulmarg, India during the magnetic storm of 6-7 March, 1986(2007) R. Singh; Abhay K. Singh; D. Singh; R.P. SinghDuring the analysis of archived VLF data from Indian low latitude ground stations, some discrete VLF emissions recorded at the low latitude ground station Gulmarg (geomagnetic latitude 24°26′N; geomagnetic longitude 147°09′E, L = 1.28) during moderate magnetic storm activity (Σ KP- = 32, Kp index varies from 4 to 6 during the observation period) on 6/7 March, 1986 are presented in this paper. The dynamic spectra of these discrete VLF emissions were observed along with tweeks and its harmonics, which is interesting and complex to explain. In most of the events the harmonic frequency of tweeks correlates with the starting frequency of harmonics of discrete emissions. In order to explain the observed features of discrete VLF emissions, we propose cyclotron resonance interaction between whistler mode wave and energetic electrons of inner radiation belt as possible generation mechanism. An attempt is also made to determine parallel energy, anisotropy and wave growth relevant to the generation process of VLF emissions.PublicationConference Paper In a search for a chiral symmetry in 102Rh(Institute of Physics Publishing, 2014) M.S. Yavahchova; D. Tonev; N. Goutev; P. Petkov; G. De Angelis; R.K. Bhowmik; R.P. Singh; S. Muralithar; N. Madhavan; R. Kumar; M. Kumar Raju; J. Kaur; G. Mohanto; A. Singh; N. Kaur; R. Garg; A. Sukla; Ts K. Marinov; S. BrantExcited states in 102Rh were populated in the fusion-evaporation reaction 94Zr(nB, 3n)102Rh at a beam energy of 36 MeV, using the INGA spectrometer at IUAC, New Delhi. The angular correlations and the electromagnetic character of some of the γ-ray transitions observed in 102Rh were investigated in detail. A new candidate for a chiral twin band was identified in 102Rh for the first time.PublicationConference Paper Modeling of VHF scintillation observed at low latitude(Institute of Physics Publishing, 2010) S.B. Singh; K. Patel; R.P. Patel; A.K. Singh; R.P. SinghThe VHF amplitude scintillations recorded during the period from January 1991 to December 1993 in the declining phase of a solar cycle and April 1998 to December 1999 in the ascending phase of the next solar cycle and from January 2008 to July, 2008 at low latitude station Varanasi (geomag. lat. 14° 55′ N, long. 154° E, Dip angle 37.3°, Sub-ionospheric dip 34°) have been analyzed to study the characteristics of ionospheric irregularities during the active solar and magnetic periods. In this paper, the expression for flux tube integrated linear growth rate of irregularities supposed to be produced through generalized Rayleigh-Taylor instability (GRTI) have been derived. Realistic atmospheric and ionospheric density model inputs are used to compute R-T growth rates for a range of geophysical conditions. The derived parameters of irregularities from scintillation data observed at low latitude are compared with computed values. An attempt is made to produce a model for ionospheric low latitude irregularities. © 2010 IOP Publishing Ltd.