NOPR Collection:

Ground state potential energy surface of HNS-NSH systems: A density functional study

1995-10-01T00:00:00Z

Title: Ground state potential energy surface of HNS-NSH systems: A density functional study Authors: Tandon, H C; Ray, N K Abstract: Density functional theory (DFT) calculations have been made to study the potential energy surface of HNS system. Calculated equilibrium geometries of HNS, NSH and the transition state (TS) are in good agreement with the results of other high level ab-initio studies. HNS is predicted to be more stable than NSH (25 kcal mol^-1). The energy barrier for the isomerization of HNS to NSH is predicted to be 70 kcal mol^-1. Calculated atomization energies, vibrational frequencies, and zero point vibrational energies are in excellent agreement with other estimates. The adequacy of the functional used, here has also been tested by examining the results for HCN-HNC systems for which both experimental and high quality ab-initio results are available in the literature. Page(s): 757-759

Electric dipole moment derivatives for germane computed by density functional method

1995-10-01T00:00:00Z

Title: Electric dipole moment derivatives for germane computed by density functional method Authors: Papousek, D; Papouskova, D; Chong, Delano P Abstract: The first derivatives of the electric dipole moments along the symmetry coordinates have been computed for D₃GeH and DGeH₃ by means of the deMon density functional program [St-Amant A & Salahub D R, Chern phys Lett, 169 (1990) 387] and transformed into those for GeH₄, GeD₄, and H₂GeD₂using relations between the symmetry coordinates for T_d, C₃_v and C₂_v molecules. Dipole moment derivatives along the normal coordinates of vibration have been calculated using the force field for GeH₄ and compared with the available experimental data. Page(s): 760-764

Basicities of acetaldehyde and acetone at the ground and low lying excited states

1995-10-01T00:00:00Z

Title: Basicities of acetaldehyde and acetone at the ground and low lying excited states Authors: Thakuria, T; Medhi, C Abstract: Proton affinities (PAs) of acetaldehyde and acetone at the ground and excited states are calculated by INDO(MCSCF)OGM method. Structural changes of the molecules due to electronic reorganization after excitation and protonation are observed. Calculations are carried out for a rigid monomer configuration of the molecule. The calculated PAs are scaled with respect to the ground state PA of formaldehyde. It is found that PA increases with the order of the molecules H₂CO > CH₃CHO > (CH₃)₂CO.The computed PA is not additive with respect to each methyl substitution. Page(s): 765-770

Prototropic reactions of 6-aminoindazole in cationic and anionic micelles

1995-10-01T00:00:00Z

Title: Prototropic reactions of 6-aminoindazole in cationic and anionic micelles Authors: Saba, Subit K; Pandey, Siddartha; Dogra, Sneh K Abstract: Spectral characteristics of 6-aminoindazole (6-INH₂) have been studied in different concentrations of sodium dodecyl sulphate (SDS) and cetyltrimethylammonium bromide (CTAB) and at different pH. The results have shown that the partition coefficient of 6-INH₂ into the micelles is very small, because of its polar nature. Deprotonation reaction occuring at the micellar interface is from - NH₂ group and the monoanion thus formed is fluorescent This behaviour is different from that occuring in pure aqueous medium. The apparent pK_a values for the monocation-neutraI molecule and neutral molecule-monoanion equilibria have been determined at different detergent concentrations. Page(s): 771-777