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排序方式: 共有132条查询结果,搜索用时 15 毫秒
91.
Alberto Gambi Udai P. Verma Manfred Winnewisser Guy Guelachvili 《Journal of Molecular Spectroscopy》1984,108(2):264-275
The high-resolution infrared spectrum of 13C-diazirine was recorded using a high-information Fourier transform spectrometer with a resolution of 0.0054 cm?1. The rovibrational structure of the ν3 fundamental at 1458.1884 cm?1, which is an A-type parallel band (13CH2 deformation) was assigned and analyzed with extensive use of modern methods of spectrum simulation. The rovibrational assignment and the molecular constants determined for the excited vibrational level of this band are given. 相似文献
92.
The microwave and millimeter wave spectrum of 12CH318OH has been observed in the frequency region 7.9–200 GHz. Both a- and b-type transitions have been assigned and measured. This spectrum was analyzed using the method of Lees and Baker, and rotational constants, torsional constants, centrifugal distortion constants, the barrier to internal rotation and moments of inertia have been evaluated. The barrier has been found to be 374.91 ± 0.18 cm?1, in good agreement with that of 12CH316OH. The moments of inertia were combined with those of other isotopic species to give a full substitution structure. To assist searches for this molecule in interstellar space a table of predicted frequencies of astrophysically interesting transitions is presented. 相似文献
93.
Koichi Yamada Manfred Winnewisser Gisbert Winnewisser L.B Szalanski M.C.L Gerry 《Journal of Molecular Spectroscopy》1980,79(2):295-313
The rotational spectrum of isothiocyanic acid was measured for the isotopically enriched species H15NCS and HN13CS as well as HNC34S in natural abundance. In the frequency range from 8 to 240 GHz the a-type R-branch transitions were measured for all three isotopic species. The qQ1 transitions were identified in the microwave region for H15NCS and HN13CS. The rotational and centrifugal distortion constants were determined using Watson's Hamiltonian in the S reduction, extended empirically to higher order terms in the angular momentum. The molecular structure of isothiocyanic acid was reevaluated using a modified substitution method and the NCS chain was found to be bent: , , , ∠HNC = 131.7°, and ∠NCS = 173.8°. The molecule has the trans conformation. 相似文献
94.
95.
96.
Thirty b-type P, Q and R branch rotational transitions and nineteen a-type Q and R branch transitions have been detected and measured for the slightly asymmetric rotor molecule D14N3 in the frequency range from 8 to 340 GHz. The information obtained from the analysis of the observed frequencies are greatly improved values of the K-dependent parameters AO = 344746.589(64) MHz, and DK = 92.242(33) MHz, refined values for the rotational constants BO and CO, a complete set of quartic centrifugal distortion constants and several sextic distortion constants. Both a and b components of the electric dipole moment were determined giving a total dipole moment of μ = 1.76(5) debye. 相似文献
97.
Winnewisser G Lewen F Thorwirth S Behnke M Hahn J Gauss J Herbst E 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(22):5501-5510
Gas-phase oxadisulfane (HSOH), the missing link between the well-known molecules hydrogen peroxide (HOOH) and disulfane (HSSH), was synthesized by flash vacuum pyrolysis of di-tert-butyl sulfoxide. Using mass spectrometry, the pyrolysis conditions have been optimized towards formation of HSOH. Microwave spectroscopic investigation of the pyrolysis products allowed-assisted by high-level quantum-chemical calculations--the first measurement of the rotational-torsional spectrum of HSOH. In total, we have measured approximately 600 lines of the rotational-torsional spectrum in the frequency range from 64 GHz to 1.9 THz and assigned some 470 of these to the rotational-torsional spectrum of HSOH in its ground torsional state. Some 120 out of the 600 lines arise from the isotopomer H(34)SOH. The HSOH molecule displays strong c-type and somewhat weaker b-type transitions, indicating a nonplanar skew chain structure, similar to the analogous molecules HOOH and HSSH. The rotational constants (MHz) of the main isotopomer (A=202 069, B=15 282, C=14 840), determined by applying a least-squares analysis to the presently available data set, are in excellent agreement with those predicted by quantum-chemical calculations (A=202 136, B=15 279, C=14 840). Our theoretical treatment also derived the following barrier heights against internal rotation in HSOH (when in the cis and trans configurations) to be V(cis) approximately equal to 2216 cm(-1) and V(trans) approximately equal to 1579 cm(-1). The internal rotational motion results in detectable torsional splittings that are dependent on the angular momentum quantum numbers J and K(a). 相似文献
98.
Winnewisser G 《Analytical and bioanalytical chemistry》1996,355(5-6):571-575
The space between the stars is not void, but filled with interstellar matter, mainly composed of dust and gas, which gather in large interstellar clouds. In our Galaxy these interstellar clouds are distributed along a thin, but extended layer which basically traces out the spiral distribution of matter: the stars, the gas, and the dust component. Up to the present time more than 100 different molecules have been identified in interstellar molecular clouds. The majority of the interstellar molecules constitute carbon containing organic substances. During the past years, overwhelming evidence has been gathered, mainly through spectroscopic observations, that interstellar molecular clouds provide the birthplaces for stars. In fact detailed high spectral and spatial resolution spectroscopic measurements reveal physical and chemical processes of the intricate star formation process. 相似文献
99.
The rotational spectra of formaldehyde, H212C16O and its isotopic species H213C16O, H212C18O, and H213C18O have been investigated in the ground vibrational state in the frequency region between 8 and 460 GHz. For most cases in which measurements of the a-type R- and Q-branch transitions already existed the accuracy of the line position has been improved to about 10 kHz. For H212C16O and H213C16O a large number of ΔKa = ±2 transitions were measured with similar accuracy. These new data when combined with all other available data and appropriate weightings lead to a set of ground state parameters which for the first time are compatible with infrared and ultraviolet data. The rotational constants (and 3σ standard deviations) obtained using Watson's A-reduced Hamiltonian are:
H212C16O | H213C16O | H212C18O | H213C18O | |
A/MHz | 281 970.572 (24) | 281 993.258(135) | 281 961.94 (39) | 281 985.00 (93) |
B/MHz | 38 836.0456(13) | 37 811.0887(25) | 36 904.1693(66) | 35 859.256(10) |
C/MHz | 34 002.2034(12) | 33 213.9790(25) | 32 511.5311(63) | 31 697.868(10) |