Browsing by Author "Ghosh A."

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    Comparative analysis of metabolites in contrasting chickpea cultivars
    (Springer, 2019) Ghosh A.; Dadhich A.; Bhardwaj P.; Babu J.N.; Kumar V.
    Chickpea (Cicer arietinum L.) is a good source of nutrients for animals and human consumption. In the present study, we analyzed the anthocyanin and total phenolic contents in two contrasting (desi and kabuli) chickpea cultivars. The quantification of anthocyanins showed higher amount in desi as compared to kabuli chickpea. The total phenolic contents was estimated in desi and kabuli chickpea using two different solvents (50% Acetone and 70% Methanol extracts) for coverage of all potential phenolic compounds. In continuation, desi chickpea culitvars (himchana and ICC4958) were found to be significantly higher total phenolic contents (in both solvent extracts) as compared to kabuli cultivars (JGK-03 and L-552). Higher phenolic contents was found to be directly correlated to higher anthocyanin contents in desi as compared to kabuli chickpea. The volatile organic compounds were also analyzed using gas chromatography mass spectroscopy technique in both cultivars. The significant compositional differences in volatile organic composition (polar and non-polar) of desi and kabuli cultivars were also found to be noticed using two different solvent extractions (methanol and chloroform). The comparative analysis of volatile organic acids in methanolic and chloroform extracts of desi cultivars (himchana and ICC4958), kabuli cultivars (JGK-03 and L-552) and between desi and kabuli cultivars was also carried out for in-depth understanding of the differential patterns of low molecular weight metabolites. Six metabolites were found to be common in all four selected cultivars in chloroform extracted samples, while four were found to be common in all four selected cultivars in methanolic extracted samples. The remaining detected metabolites are uncommon among different cultivars and represented as cultivar specific signatory metabolites. In conclusion, the present investigation revealed higher anthocyanin and phenolic contents in desi cultivars as compared to kabuli cultivars and differential accumulation of volatile organic compounds in chickpea cultivars. The metabolite alterations among desi and chickpea cultivars could be the potential attribute for diversity, resilience and commercial usuages.
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    Electronic spectroscopy of carbon chains (C2 n +1, n = 7-10) of astrophysical importance. I. Quantum chemistry
    (American Institute of Physics Inc., 2019) Reddy S.R.; Ghosh A.; Mahapatra S.
    Carbon chains have been predicted to be potential carriers of diffuse interstellar band features in astrophysical observations. Motivated by numerous predictions, we set out to carry out extensive ab initio quantum chemistry calculations to establish the ground and excited electronic potential energy surfaces and their coupling surfaces for carbon chains containing an odd number of carbon atoms (C2n+1, n = 7-10). Vibronic coupling models are established with the aid of the calculated electronic energies to investigate nuclear dynamics from first principles. The latter are reported in Ghosh et al. [J. Chem. Phys. 151, 054304 (2019)]. The mentioned carbon chains possess a linear cumulenic structure at the equilibrium minimum of their electronic ground state, and an electronic excited state of the ?u+1 term appears to be extremely bright optically and absorbs in the visible region of the electromagnetic spectrum. Vertical excitation energy of this state decreases and transition dipole moment increases, and as a result, the oscillator strength of this state linearly increases with an increase of the chain length. There are states belonging to 1?g, 1?u, ?g+1, 1?g, and 1?u terms, in the immediate vicinity of the ?u+1 state, which are optically dark but can gain intensity through vibronic coupling with the optically bright ?u+1 state. Construction of a coupling scheme considering the Renner-Teller coupling within the degenerate ? states and pseudo-Renner-Teller coupling between the Renner-Teller split component states as well as with the nondegenerate ? states is another motivation of this work. The coupled-state Hamiltonian is constructed in a diabatic electronic basis in terms of the dimensionless normal coordinates of the vibrational modes of the carbon chains. Both Renner-Teller and pseudo-Renner-Teller types of couplings are included in the Hamiltonian. The theoretical results are discussed in relation to the experimental findings. � 2019 Author(s).
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    Electronic spectroscopy of carbon chains (C2 n +1, n = 7-10) of astrophysical importance. II. Quantum dynamics
    (American Institute of Physics Inc., 2019) Ghosh A.; Reddy S.R.; Mahapatra S.
    In continuation with Paper I [S. R. Reddy et al., J. Chem. Phys. 151, 054303 (2019)], the vibronic structure and dynamics of the 1?u+ electronic state of C15, C17, C19, and C21 chains in the coupled manifold of 1?u+-1?g-1?u- 1?g+ electronic states have been investigated in this paper. The model vibronic Hamiltonian developed through extensive ab initio quantum chemistry calculations in Paper I is employed, and first principles nuclear dynamics calculations are carried out to obtain the photoabsorption band of the 1?u+ electronic state. Both time-independent and time-dependent quantum mechanical calculations are carried out to precisely locate the vibrational levels, assign them with the progression of vibrational modes, and elucidate the impact of both Renner-Teller and pseudo-Renner-Teller couplings on them. The nonradiative decay of the 1?u+ electronic state is studied, and it is found that the decay rate is comparable with the prediction made for them to be qualified as a carrier of diffuse interstellar bands in the literature. The theoretical results are found to be in good accord with the available experimental results.