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71.
M Alcolea Palafox V K Rastogi C Singh R P Tanwar 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2001,57(12):2373-2389
Geometry, vibrational frequencies, atomic charges and several thermodynamic parameters (the total energy, the zero point energy, the rotational constants and the room temperature entropy) were calculated using ab initio quantum chemical methods for 2,3-difluorobenzonitrile molecule. The results were compared with experimental values. With the help of two specific scaling procedures, observed FTIR and Raman vibrational frequencies were analysed and assigned to different normal modes of the molecule. The error obtained was in general very low. Other general conclusions have also been deduced. 相似文献
72.
Correlation between deformation bleaching and mechanoluminescence in coloured alkali halide crystals
The present paper reports the correlation between deformation bleaching of coloration and mechanoluminescence (ML) in coloured
alkali halide crystals. When the F-centre electrons captured by moving dislocations are picked up by holes, deep traps and other compatible traps, then deformation
bleaching occurs. At the same time, radiative recombination of dislocation captured electrons with the holes gives rise to
the mechanoluminescence. Expressions are derived for the strain dependence of the density of colour centres in deformed crystals
and also for the number of colour centres bleached. So far as strain, temperature, density of colour centres, E
a and volume dependence are concerned, there exists a correlation between the deformation bleaching and ML in coloured alkali
halide crystals. From the strain dependence of the density of colour centres in deformed crystals, the value of coefficient
of deformation bleaching D is determined and it is found to be 1.93 and 2.00 for KCl and KBr crystals, respectively. The value of (D+χ) is determined from the strain dependence of the ML intensity and it is found to be 2.6 and 3.7 for KCl and KBr crystals,
respectively. This gives the value of coefficient of deformation generated compatible traps χ to be 0.67 and 1.7 for KCl and KBr crystals, respectively. 相似文献
73.
Poonam Tandon V. D. Gupta O. Prasad Shantanu Rastogi V. P. Gupta 《Journal of Polymer Science.Polymer Physics》1997,35(14):2281-2292
Poly(L -methionine) (PMet) is one of the two sulfur containing polyamino acids. Raman, FTIR spectra, and heat capacity measurements of PMet have been well interpreted through the normal mode analysis and the density of states derived therefrom. Earlier interpretation of heat capacity data is limited because it is based on the Tarasov model, wherein the concept of group frequency and skeletal similarity are used. A special feature of some dispersion curves is their tendency to bunch in the neighborhood of the helix angle. This has been attributed to the presence of strong intramolecular interactions. Repulsion between the dispersion curves is also observed. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 2281–2292, 1997 相似文献
74.
75.
R. G. Pillay A. K. Rastogi A. K. Grover V. Balasubramanian P. N. Tandon 《Hyperfine Interactions》1988,40(1-4):413-416
The reported double transition in the series Ce(Fe1–xCox)2 for x<0.3 has been shown to be due to spin reorientation from Mossbauer measurements at57Fe. It is suggested that the competing interactions with randomly substitution of Fe by Co atoms causes a quasi random freezing which results in abrupt loss of magnetization. 相似文献
76.
Manju K. Saroj Ritu Payal Sapan K. Jain Neera Sharma Ramesh C. Rastogi 《Journal of inclusion phenomena and macrocyclic chemistry》2018,90(3-4):305-320
The study focuses on the formation of inclusion complexes of indole chalcone (IC) derivatives with β-cyclodextrin (β-CD), which involves absorption and steady state fluorescence spectroscopies. The formation of inclusion complexes is validated by increase in their absorbance and fluorescence intensity as well as the blue shift with increase in the concentration of β-CD in the aqueous solution. The stoichiometries and binding constants (Kin) of these complexes have been investigated by monitoring their absorbance and fluorescence spectral profiles. The data are analyzed by Benesi–Hildebrand plots as well as Job’s method, which indicate 1:1 stoichiometry of IC:β-CD complexes. Fluorescence measurements are also used to investigate the effect of temperature on the stability of inclusion complexes. Stability of IC:β-CD complexes is significantly affected with variation in substituents on the phenyl ring and temperature. It is observed that the stability of the inclusion complex decreases with increase in temperature; Kin(293 K)?>?Kin(298 K)?>?Kin(308 K)?>?Kin(318 K). All the experimental results and the geometrical data obtained using PM3 semiempirical method illustrate the partial inclusion of IC derivatives from the phenyl ring side in β-CD cavity. The binding process of IC derivatives with β-CD is found to be exothermic in nature and seems to be controlled by electrostatic and hydrophobic forces. The binding free energies calculated using semiemprical PM3 method for IC:β-CD complexes are found to be in the order: I?<?OH–I?<?Me–I?<?OMe–I?<?NH2–I, which largely supports the findings based on the experimental binding constants. 相似文献
77.
Feng Jun Chernova Natasha A. Omenya Fredrick Tong Lingyue Rastogi Alok C. Stanley Whittingham M. 《Journal of Solid State Electrochemistry》2018,22(4):1063-1078
Journal of Solid State Electrochemistry - Hybrid supercapacitors using asymmetric, LiFePO4 (LFP) lithium intercalation and electric double layer activated carbon (AC) electrodes combining the high... 相似文献
78.
79.
V.K Rastogi C.B Arora S.K Singhal D.N Singh R.A Yadav 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》1997,53(14):2505-2510
Raman spectrum of 2,6-difluorobenzonitrile in the powder form has been recorded in the region 50–4000 cm−1 on a Jasco K-500 spectrophotometer using the 488.0 nm radiation from an argon laser. IR spectra in the region 200–4000 cm−1 have been recorded in KBr pellet and nujol mull on a Nicolet DX spectrometer and in liquid and vapour phases on a Jasco FTIR/7000 spectrometer. Using these observed frequencies force field calculations for the planar and non-planar modes have been carried out assuming a general valence force field. 相似文献
80.
The stability constants of the fluoride complexes of cerium(IV) in 1 M (HClO(4), NaClO(4)) medium have been measured potentiometrically using a fluoride ion-selective electrode. Quantitative oxidation of cerium to its tetravalent state and its stabilisation in the perchlorate medium were accomplished by oxidation with AgO followed by quick addition of a known amount of fluoride ion. This procedure ensures stability of the oxidation state and prevents hydrolysis and polymerisation of Ce(IV). Logarithms of the average values of beta(1), beta(2), beta(3) and beta(4) were estimated to be 7.57+/-0.04, 14.50+/-0.03, 20.13+/-0.37 and 24.14+/-0.10 respectively. 相似文献