排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
A. N. Yunuskhodzhaev EB. Shamuratov A. S. Batsanov S. A. Talipov 《Chemistry of Natural Compounds》1992,27(6):743-744
A single crystal of (RS)-carnitine hydrochloride has been obtained, and its crystal structure has been refined by an x-ray structural experiment.Tashkent Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 842–844, November–December, 1991. 相似文献
2.
The first high-resolution study on germanium tetrafluoride is reported. We used a monoisotopic sample of (70)GeF(4). The FTIR spectra of the two infrared active fundamentals, namely the nu(4) (bending) and nu(3) (stretching) modes, were recorded at a temperature of ca. 210 K and a resolution (1/maximum optical path difference) of 0.0031 and 0.0023 cm(-1), respectively. These spectra were analyzed using the STDS software developed in Dijon. In both cases, we obtained a fit with a root mean square better than 1x10(-3) cm(-1). Both bands show very regular structures with no detectable perturbation. Copyright 2001 Academic Press. 相似文献
3.
Gnida M Margulès L Cosléou J Bocquet R Demaison J Mkadmi EB Bürger H Harder H Mäder H 《Journal of Molecular Spectroscopy》2000,200(1):40-54
The present paper deals with the analysis of the microwave, millimeter-wave, and infrared spectra of (28)SiHF(3) in its ground, v(6) = 1 and v(4) = 1 excited states. The former was observed up to 1055 GHz leading to the determination of one octic centrifugal distortion constant, L(J) = -0.0749(55) μHz. Furthermore the interaction term ||h(3,GS) || = 1.1032(70) mHz has been fitted from splittings of six K = 3 lines. The excited states have been regarded as isolated ones. This enabled fits according the Q-, D-, and QD-reduction schemes proposed by E. I. Lobodenko, O. N. Sulakshina, V. I. Perevalov, and Vl. G. Tyuterev, (J. Mol. Spectrosc. 126, 159-170 (1987)) and further developed by J. K. G. Watson, C. Gerke, H. Harder, and K. Sarka, (J. Mol. Spectrosc. 187, 131-141 (1997)) and Harder (J. Mol. Spectrosc. 194, 145 (1999)). A multiple fit analysis was performed confirming the assumption that the excited states are not affected by intervibrational resonances. Finally the millimeter spectrum of (29)SiHF(3) and (30)SiHF(3) in their ground state was also measured up to 460 GHz and accurate rotational and centrifugal distortion parameters were derived. Copyright 2000 Academic Press. 相似文献
4.
Badaoui M Sari-Zizi NB Graner G Mkadmi EB Bürger H Pracna P 《Journal of Molecular Spectroscopy》2000,200(1):72-88
The nu(2) (A(1), 710.157 cm(-1)) and nu(5) (E, 701.717 cm(-1)) fundamental bands of D(3)(28)SiF have been studied by FTIR spectroscopy with a resolution of 2.4 x 10(-3) cm(-1). We assigned 1648 lines for the parallel band (J(max) = 50, K(max) = 21), 4279 for the perpendicular band (J(max) = 52, K(max) = 27), and in addition 671 perturbation-allowed transitions (J(max) = 50, K(max) = 12). The nearly degenerate v(2) = 1 and v(5) = 1 states are linked by (DeltaK = +/-1, Deltal = +/-1) and (DeltaK = +/-2, Deltal = -/+1) interactions, while the l(5) = +/-1 levels of nu(5) interact also by l(2, -1), l(2, 2), and l(2, -4) interactions. The first model with 36 free parameters, taking into account all these resonances through a nonlinear least-squares program, gave standard deviations of 1.56 x 10(-4) cm(-1) for 5997 nonzero-weighted IR data and 138 kHz for 8 MW data from the literature. The second model, in which the main Coriolis term was constrained to a force field value, used 37 parameters and gave similar standard deviations. A new determination of the A(0) and D(0)(K) ground state parameters was performed by two methods: either using differences between "forbidden" transitions differing by 3 in K or letting A(0) and D(0)(K) free in the global fit. The values obtained are fully compatible with those obtained previously by the "loop method." Copyright 2000 Academic Press. 相似文献
5.
Trapped modes in acoustic waveguides 总被引:2,自引:0,他引:2
Davies EB; Parnovski L 《The Quarterly Journal of Mechanics and Applied Mathematics》1998,51(3):477-492
6.
7.
Christoph Bartel Peter Botschwina Hans Bürger Antonio Guarnieri nne Heyl Aiko Huckauf Dieter Lentz Tatjana Merzliak El Bachir Mkadmi 《Angewandte Chemie (International ed. in English)》1998,37(20):2879-2882
Vacuum pyrolysis of the precursor complex [(CO)5Cr(CN−CCl=CF−CN)] resulted in the isolation and structure elucidation by molecular spectroscopy of isomer 1 . According to ab initio calculations 1 is 109 kJ mol−1 less stable than NC−C≡C−CN, which has been known for some time. An accurate equilibrium structure for 1 has been determined with mixed experimental and theoretical methods. 相似文献
8.
F. WintherM. Schönhoff A. Huckauf E.B. Mkadmi 《Journal of Molecular Spectroscopy》2002,216(2):374-378
The hot bands in the ν1, ν2, and ν3 band systems of NC-CC-NC (3-isocyano-2-propynenitrile) have been investigated and transitions from nv9-levels with n up to 4 have been identified. Two weak bands have also been observed in the gas phase infrared spectrum at 2157 and 2410 cm−1, of which the latter is probably 2v4. A preliminary investigation of some analogous hot bands in the v4 band system of the related molecule NC-CC-CN (dicyanoacetylene) is also reported. 相似文献
9.
A. N. Yunuskhodzhaev EB. Shamuratov A. S. Batsanov S. A. Talipov 《Chemistry of Natural Compounds》1991,27(6):743-744
A single crystal of (RS)-carnitine hydrochloride has been obtained, and its crystal structure has been refined by an x-ray structural experiment. 相似文献
10.
The infrared spectrum of isotopically pure CH2 79BrCl has been recorded at a resolution of 0.0025?cm?1 and 0.0023?cm?1 (FWHM) in the range 600–1600?cm?1 with a Bruker IFS 120 HR Fourier transform spectrometer in Wuppertal. Here we report the full rotational analysis of the ν3 and ν9 fundamentals of the most abundant species CH2 79Br35Cl . Improved ground state constants, up to quartic terms, have been obtained from ground state combination differences (GSCD) involving transitions of the fundamentals ν3, ν4, ν5 and ν9. Both ν3 and ν9 transitions were fitted to a Watson-type Hamiltonian in the S-reduction, yielding accurate molecular constants for the ν3 and ν9 excited states. Small local perturbations were observed in both bands. Prominent features in the spectra were assigned to the ν3 and ν9 fundamentals of the CH2 79Br37Cl isotopic species and the hot-bands ν3+ν6???ν6 and ν9+ν6???ν6 of CH2 79Br35Cl. 相似文献