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1.
A new scheme for controlling photodissociation through preparation of a variationally optimized linear superposition of field free vibrational eigenstates is applied for selective control of IBr and HI dissociation. The dependence of photodissociation on various field parameters and initial conditions is examined to investigate the mechanistic basis of selective control. The parametric equations of motion approach for determining vibrational dynamics as a function of field parameters without having to solve the time dependent Schrödinger equation explicitly for each field parameter separately is outlined and its use to identify field characteristics which will provide the requisite population mix represented by the optimal linear superposition of vibrational states is advocated. 相似文献
2.
Vandana Singh Ashutosh TiwariDevendra Narayan Tripathi Tulika Malviya 《Tetrahedron letters》2003,44(39):7295-7297
O-Methylation is of outstanding importance in structural polysaccharide chemistry. A novel method for the methylation of polysaccharides using microwave (MW) irradiation is described. Seed gum from Cyamopsis tetragonolobus (Guar) was fully methylated with dimethyl sulphate and sodium hydroxide using 100% microwave power for 4 min in 68% yield. The completely methylated seed gum thus obtained was hydrolyzed by 70% formic acid followed by 0.5N H2SO4 under full microwave power for 1.16 and 1.66 min, respectively. The partially methylated monosaccharides were separated and identified. 相似文献
3.
Low-temperature property investigation of the lead indium-niobate-lead nickel-niobate solid solution
Edward F AlbertaAmar S Bhalla 《Journal of Physics and Chemistry of Solids》2002,63(9):1759-1769
The complex perovskite solid solution (1−x) Pb(In1/2Nb1/2)O3-(x) Pb(Ni1/3Nb2/3)O3 has been successfully prepared by the Columbite precursor method. The temperature dependencies of the dielectric constant and pyroelectric coefficient were measured between −261 and 200 °C. Relaxor ferroelectric behavior has been noticed in all compositions across the solid solution. The room-temperature electrostrictive coefficient, Q33, was 1.83×10−2 C2/m4 for x=0.10. No room-temperature piezoelectric activity was detected; however, upon cooling to −261 °C the maximum coupling coefficients kp=29%, kt=11%, and k33=31% were observed for the composition x=1.00. 相似文献
4.
Out of a total statistics of 896139La+Ag(Br) interactions, 128 interactions having multiplicity of target fragments (Z⩾1)⩾8 and projectile fragments (Z⩾2)⩾4 have been selected. They correspond to quasi-peripheral interactions. Azimuthal angle correlation between sources of
target fragments (TFs) and projectile fragments (PFs) shows the existence of bounce-off effect. Using data of La+Ag(Br) and84Kr+Ag(Br) reactions it is shown that individual helium [Z=2, PFs] and heavier fragment [Z⩾3, PFs] show different emission characteristics. Further, a two prong correlation functionT(Φ
ij
) plotted for heavier fragments and helium fragments separately, indicates the possibility of existence of different physical
conditions. This observation is supported by the different momentum widths of helium fragments and heavier fragments. From
the momentum width data of Kr+Ag(Br) reactions normalized density comes out to be ≈4.7. Using quasi-elastic kinematics for
the bounce-off nuclei, the excitation energy has been computed from the experimental data of flow angles. The strength of
bounce-off seems to decrease with the increase of excitation energy or temperature. 相似文献
5.
6.
Adamovich MI Aggarwal MM Alexandrov YA Ameeva ZV Andreeva NP Anzon ZV Arora R Badyal SK Bhalla KB Bhasin A Bhatia VS Bubnov VI Burnett TH Cai X Chasnikov IY Chernova LP Chernyavski MM Dressel B Eligbaeva GZ Eremenko LE Friedlander EM Gadzhieva SI Gaitinov AS Ganssauge ER Garpman S Gerassimov SG Gill A Grote JG Gulamov KG Gulyamov UG Gupta VK Hackel S Heckman HH Haung H Judek B Kachroo S Kadyrov FG Kalyachkina GS Kanygina EK Kaul GL Kaur M Kharlamov SP Koss T Kumar V Lal P Larionova VG 《Physical review letters》1990,65(4):412-415
7.
Biscyclopentadienyl molybdenum (VI) oxide dichloride (I) and bisindenyl molybdenum (VI) oxide dichloride (II) react with various thiols in tetrahydrofuran and from the complexes of the type (C3H5)2MoO (R2) and (C9H7)2MoO (R2) wherein R may be S CH8, S C2H5, S C3HN7, S C3H7, S C4Hn9, or S C4H3 or S C3H11. The preparation, thermal stabilities, physical characteristics and infrared spectra of these complexes have been studied in this paper. 相似文献
8.
The deoxygenation of a variety of sulfoxides, selenoxides, telluroxides, sulfones, selenones and tellurones has been reported with Mg-MeOH at room temperature in nearly quantitative yields. The deoxygenation is proposed to proceed by SET from Mg to the substrate. 相似文献
9.
Synthesis and binding studies of new bis-calix[4]arenes containing aromatic and heteroaromatic units
A series of new bis-calix[4]arenes containing different aromatic and heteroaromatic moieties have been synthesized. The complexing behavior of these bis-calix[4]arenes have been studied towards different metal ions and it has been found that these bis-calix[4]arenes bind silver ions selectively over other metal ions. The complexation has been studied by liquid-liquid extraction and by NMR and IR spectroscopy. 相似文献
10.
Krishna C. Joshi Renuka Jain Anshu Dandia Vandana Sharma 《Journal of heterocyclic chemistry》1986,23(1):97-99
A novel system 2-oxo-1′,2′,4′,5′-tetrahydrospiro[3H-indole-3,3′-1,2,4,5-tetrazine]-6′-thione has been synthesized by the treatment of fluorinated isatins with thiocarbohydrazide in aqueous ethanolic medium. Under exactly similar conditions, N-acetylisatin gave exclusively thiocarbohydrazone. The spiro product, on treatment with acetic acid, gave fluorinated isoindigo. Characterization of these products have been done by elemental analyses, ir, pmr and mass spectral studies. 相似文献