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51.
52.
Phonon anomalies in two intermediate valence compounds (IVC), SmS and Sm0·75Y0·25S have been investigated using breathing shell model (BSM). The BSM includes breathing motion of electron shells of the rare
earth atom due tof−d hybridization. The phonon dispersion curves of IVC, calculated from the present model, agree well with the measured data.
One-phonon density of states calculated from the present model compares well with the Raman spectra. 相似文献
53.
Sankar P. Sanyal 《Journal of Physics and Chemistry of Solids》1981,42(5):429-432
A detailed investigation of the phonon dispersion and static and anharmonic properties has been carried out for ND4I using an extended three-body force shell model (ETSM) developed by Singh and Chandra. The ETSM results for phonon dispersion show better agreement with the experimental data than those obtained from the deformation dipole and rigid shell models. Calculated values have also been obtained for some other properties. 相似文献
54.
The 13C chemical shifts and one-bond carbon-hydrogen coupling constants have been obtained for some hydroxycoumarins and their corresponding acetoxy and methoxy derivatives. The changes in the one-bond carbon-hydrogen coupling constants resulting from the conversion of a hydroxy group to an acetoxy group represent a simple method of assignment of the 13C NMR signals in coumarins which contain one or more hydroxy groups in the benzenoid ring. 相似文献
55.
Manas Banerjee Sankar Prasad Bhattacharyya 《International journal of quantum chemistry》1982,22(4):775-782
The considerations of Walsh rules are extended to rationalize the loss of planarity in the 1,3nπ* states of simple carbonyl and thiocarbonyl molecules. The role of Fermi correlation in shaping the differences between conformations in the singlet and the triplet state is emphasized. The role played by the π* orbital is also considered. 相似文献
56.
57.
[reaction: see text] First examples of aromatic core-modified twisted heptapyrrolic systems with six meso links have been obtained via a general [3 + 4] acid-catalyzed condensation method. Despite the twisted conformation, these heptaphyrins exhibit aromaticity in solution, unlike most of the all-aza analogues. 相似文献
58.
Sankar J Rath H PrabhuRaja V Chandrashekar TK Vittal JJ 《The Journal of organic chemistry》2004,69(15):5135-5138
Three new methods for syntheses of modified oxa corroles bearing one meso free carbon in reasonably good yields are reported. The formation of the meso carbon bridge and the direct pyrrole-pyrrole linkage occur in a single step by a simple condensation and coupling with TFA as a catalyst with appropriate precursors. The reactions are optimized with different conditions by varying the meso substituents, acid catalyst concentration, and the nature of the solvent to afford corroles in good yields. 相似文献
59.
Thomas JM Raja R Johnson BF O'Connell TJ Sankar G Khimyak T 《Chemical communications (Cambridge, England)》2003,(10):1126-1127
Adipic acid (2) production currently entails use and generation of environmentally harmful materials: an efficient catalyst, consisting of nanoparticles of Ru10Pt2 anchored within the pores of mesoporous silica, facilitates the production of (2) by hydrogenating muconic acid, that may be derived biocatalytically from D-glucose. 相似文献
60.