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1.
The previously described reduction of the effective rotational Hamiltonian for semirigid molecules of C3v or D3 point group symmetry [M. R. Aliev and V. T. Aleksanyan, Opt. Spectrosc.24, 201–206 (1968)] has been extended to nonrigid molecules with a significant inversion splitting of the energy levels (e.g., NH3, H3O+, CH3?, or SiH3 molecules). Although for semirigid molecules like PH3 or AsH3, the parameters α and η′3 which appear in the terms α[J+3 + J?3, Jz]+ and η′3(J+6 + J?6) are almost completely correlated, the effects of the inversion splitting and the accidental resonance which can occur between the interacting rotational levels in nonrigid molecules make it possible to determine α and η′3 separately. The results of fitting the experimental data for 14NH3 and 15NH3 [?. Urban, Romola D'Cunha, K. Narahari Rao, and D. Papou?ek, Canad. J. Phys.62, 1775–1791 (1984); Romola D'Cunha, ?. Urban, K. Narahari Rao, L. Henry, and A. Valentin, J. Mol. Spectrosc.111, 352–360 (1985)] are in agreement with this conclusion. The possibility of the determination of the sign of η3 from a simultaneous analysis of the allowed and Δk = ±3 forbidden transitions in semirigid XY3 molecules has been discussed. 相似文献
2.
S.P. Belov L.I. Gershstein A.F. Krupnov A.V. Maslovskij Š. Urban V. Špirko D. Papoušek 《Journal of Molecular Spectroscopy》1980,84(1):288-304
Using the vibration-inversion-rotation Hamiltonian for ammonia [V. ?pirko, J. M. R. Stone, and D. Papou?ek, J. Mol. Spectrosc.60, 159–178 (1976)], a modified theory is worked out for the Δk = ±3n interactions between the inversion-rotation energy levels of NH3 which takes into account the large amplitude inversion motion. Eighty frequencies of inversion and inversion-rotation transitions and two perturbation-allowed transitions in the ν2 state of 14NH3 are measured in the far-infrared region around 1 THz (≈33 cm?1), mostly with the microwave accuracy, by the radiofrequency spectrometer with acoustic detector. By a least-squares fit of these data and the data of the infrared-microwave two-photon and infrared heterodyne measurements of the ν2 band, a set of molecular constants for the ν2 state of 14NH3 is obtained which reproduces the submillimeterwave data with the accuracy of the experiment. 相似文献
3.
Myjavcová R Marhol P Křen V Simánek V Ulrichová J Palíková I Papoušková B Lemr K Bednář P 《Journal of chromatography. A》2010,1217(51):7932-7941
Anthocyanins from the fruit Lonicera caerulea L. var. kamtschatica (blueberry honeysuckle, Caprifoliaceae) were studied via (semi)preparative chromatographic fractionation followed by MS and μLC/MS analysis. The extraction procedure was optimized with respect to analytical purposes as well as its potential use for the preparation of nutraceuticals. The highest yield of anthocyanins was obtained using acidified methanol as the extraction medium. A comparable total anthocyanin content was obtained using a mixture of methanol and acetone. However, when Lonicera anthocyanins were in contact with acetone, a condensation reaction occurred to a large extent and related 5-methylpyranoanthocyanins were found. The effect of other extraction media, including ethanol as a "green" solvent, is also discussed. The potential of two fractionation procedures for extract purification differing in their chromatographic selectivity and scale was studied (i.e. using a Sephadex LH-20 gel column and a reversed phase). Fractions obtained by both procedures were used for a detailed analysis. MS and μLC/MS(2) methods were used for monitoring anthocyanin and 5-methylpyranoderivatives content as well as identifying less common and more complex dyes (dimer of cyanidin-3-hexoside, cyanidin-ethyl-catechin-hexosides, etc.). These more complex dyes are most likely formed during fruit treatment. 相似文献
4.
An iteration procedure based on the Numerov-Cooley method of numerical integration is proposed for the computation of the potential function parameters in a one-dimensional Schrödinger equation from the experimental energies. The procedure has been tested on a calculation of the parameters of a Morse potential function and has been applied to a determination of the parameters of a double-minimum potential for the inversion motion of NH3 and ND3. 相似文献
5.
?. Urban Romola DCunha K. Narahari Rao D. Papou?ek 《Journal of Molecular Spectroscopy》1985,111(2):361-376
More than 800 Δk = ±2 and 60 Δk = ±3 forbidden transitions to the ν4 and 2ν2 vibrational levels, respectively, have been assigned in the Fourier transform spectra of 15NH3, recorded with a pathlength of 96 m. Combination differences derived from these transitions provide information on the spacing between the ground state energy levels with different rotational quantum numbers K in the interval from 0 to 16. These data along with wavenumbers of all the available allowed transitions pertaining to the ground and ν2 states have been subjected to a simultaneous least-squares analysis using two different parametrization models to obtain precise values of the inversion-rotation energy levels. 相似文献
6.
R. Angstl H. Finsterhölzl H. Frunder D. Illig D. Papoušek P. Pracna K. Narahari Rao H.W. Schrötter Š. Urban 《Journal of Molecular Spectroscopy》1985,114(2):454-472
The ν1 and ν3 fundamental bands of 14NH3 have been measured using the techniques of Fourier transform and coherent anti-Stokes Raman spectroscopy. The effective values of the band origins, rotational and centrifugal distortion constants, and parameters of the vibrational-rotational interactions have been obtained by analyzing these bands as essentially regular parallel and perpendicular bands, with the “off-diagonal” local resonance interactions excluded from the fit. The “diagonal” l-type resonance effects have been included into the analysis of the ν3 band for the +l, K = 1 and ?l, K = 2 levels. 相似文献
7.
The application of the Hougen-Bunker-Johns (HBJ) Hamiltonian to quasiplanar molecules is discussed with special emphasis on ammonia. The double-minimum potential functions of ammonia obtained in the approximation of the rigid invertor, “harmonic” nonrigid invertor, and “anharmonic” nonrigid invertor are compared from the point of view of their isotopic invariancy. The HBJ Hamiltonian can also be applied with advantage to the quantitative analysis of the transition frequencies obtained by high and very high resolution spectroscopy, as well as to the interpretation of the anomalous inversional dependence of the dipole moment function, quadrupole coupling or of the g-tensor function.The newly determined “true” barrier height for ammonia inversion by fitting the experimental data on vibration-inversion-rotation transitions is 1834 cm?1. 相似文献
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9.
Inversion splittings of the nv 2 vibrational levels in PH3 and PD3 have been calculated using a theoretical model developed by us for molecular inversion in XY3 pyramidal molecules and the slightly modified results of an ab initio SCF-LCAO-MO calculation of the double minimum potential function for PH3 by Lehn and Munsch. Inversion splittings have been predicted also for the chemical compound PMu3, where Mu is muonium. 相似文献
10.
Volodymyr Pauk Vladimír Havlíček Barbora Papoušková Petr Sulovský Karel Lemr 《Journal of mass spectrometry : JMS》2013,48(8):927-930
A new analytical protocol for identification of Prussian blue (PB) and indigo was proposed. Pigments useful for dating of artworks were detected by flow injection analysis/electrospray ionization mass spectrometry after alkalization of their suspensions in water, decomposition of PB to iron (III) hydroxide and hexacyanoferrate (II) and reduction of indigo to soluble leucoindigo using sodium dithionite. Limits of detection (PB 47 pg, indigo 59 pg) complied with requirements for analysis of microsamples of historical paintings. Potential of the developed method was proven in analysis of blue samples of two oil paintings from the 20th century. Further, PB was confirmed in a microsample from a painting of ‘Crucifixion’, St. Sebestian church on St. Hill in Mikulov, Czech Republic. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献