共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
K.D. Setzer W. Zyrnicki A.M. Pravilov E.H. Fink K.K. Das H.-P. Liebermann R.J. Buenker 《Journal of Molecular Spectroscopy》2003,217(1):127-141
Gas phase emission spectra of the hitherto unknown free radical PbLi have been measured in the NIR range with a Fourier-transform spectrometer. The emissions were observed from a fast flow system in which lead vapor in argon carrier gas was passed through a microwave discharge and mixed with lithium vapor in an observation tube. Five electronic transitions have been found in the wavenumber range 3800-10 000 cm−1. Bands from two excited states to the ground state were measured at high spectral resolution such that rotational analyses could be performed and accurate molecular parameters derived. In order to aid in the analysis of the experimental data, a series of relativistic configuration interaction calculations has been carried out to obtain potential curves for the low-lying states of PbLi and also electric dipole transition moments connecting them. As in the lighter molecules of this group, CLi and SiLi, the ground state of PbLi is found to be 3/2) with a spin splitting of about 2000 cm−1. The first excited state is (A 1/2), and two observed band systems are assigned to the transitions A→X1 and A→X2. Two more excited states, (B 3/2) and C 1/2, are identified from the observed spectra with the help of the computed data, and their spectroscopic constants are determined. In contrast to PbH and PbF, the ab initio results indicate a very complicated low-energy electronic structure for the PbLi radical, with 19 bound electronic states calculated to lie below 3 eV. 相似文献
4.
5.
6.
W. A. HERREBOUT B. J. VAN DER VEKEN A. MEDINA A. CALVO HERNÁNDEZ M. O. BULANIN 《Molecular physics》2013,111(7):1115-1124
New experimental results are reported on the relative absorption intensity distribution in the FIR spectra of HCl dissolved in liquefied Ar, Kr, and Xe at several temperatures along the liquid—vapour coexistence curve. These are treated further by applying a previously developed quantum-statistical spectral theory, which accounts for the line mixing and memory effects. Theoretical spectra are given in terms of the anisotropic potential time autocorrelation functions obtained from classical MD simulations using several empirical analytical potentials with density-adjusted well depths. Globally fair agreement between the theoretical and experimental spectra is demonstrated, except in the high frequency wings, where the theory underestimates the observed intensities. The choice of a particular radial form for the anisotropic HCl/RG potentials is found to be not critical for reproducing the experimental absorption profiles. 相似文献
7.
8.
在从头算层次上采用自洽场Hartree -Fock(SCF -HF)与密度泛函理论 (DFT)的定域自旋密度泛函SVWN和杂化泛函B3LYP方法以及 6 - 31 G(d)基组 ,计算优化了Se7环chair和boat两种分子构型。以B3LYP/ 6 - 31 G(d)优化的结构为基础 ,计算了Se7环两种构型的红外振动光谱 ,标定了这两种构型的各个简谐振动模式的对称性。计算结果与前人的理论、实验数据进行了比较。 相似文献
9.
Experimental and theoretical study of the structure and vibrational spectra of valpromide,C7H15CONH2
Nieves C. Comelli Nestor E. Massa Eduardo A. Castro Luis Bruno Blanch Alicia H. Jubert 《Journal of Raman spectroscopy : JRS》2009,40(1):6-17
In this work, we present results of the conformational and vibrational properties of valpromide (Vpd), an amide with antiepileptic activity, studied by IR and Raman spectroscopy at 300 and 77 K, and 300 K, respectively. Experimental data are compared against ab initio calculations performed at B3LYP level with the inclusion of solvatation effects. Experimental results, reinforced by theoretical calculations, point out that Vpd has three conformers on the potential energy surface, with different structures that can be identified in the CO and NH spectral regions. These conformers are defined by different angular arrays of the dihedral angles formed with the CO, C N and C〈 H, C C of the aliphatic chain bonds. The existence of different conformations and structures are discussed on the basis of results derived from electronic localization function (ELF) and natural orbital bond (NBO) analysis. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
10.
Summary A derivation of spectral energy functions for stable atmospheric boundary layers is presented for a local similarity regime.
Previous studies of this nocturnal atmospheric conditions were usually carried through purely kinematic modellizations. In
this study, the atmospheric turbulence energy content is derived from a dynamical viewpoint. This is achieved through the
use of the energy balance relation obtained by Rotta from Navier-Stokes equations. The result is an appropriate physical rooting
of the spectral energy curves known as Kaimal’s Isopleths.
The authors of this paper have agreed to not receive the proofs for correction. 相似文献
11.
12.
13.
14.
K. Rahimullah M.S.Z. Chaghtai 《Journal of Quantitative Spectroscopy & Radiative Transfer》1976,16(2):105-112
An up-to-date picture of the known np2 and np3 configurations is presented by plotting the reduced energy ? against ψ = ξp/(5F2 + ξp) according to Edlén. It is concluded that the p2 level values of S XI, Sc XVI, Ti XVII, V XVIII, Ni XV and Te III, and the p3 level values of Al VII, Si VIII, P IX, Cl X, Se II and Xe IV need to be improved. Edlén's (1972) work on n = 2 and Svensson's (1971) work on n = 3 give a very satisfactory fit to our ψ-? graphs. The (F2 - ξp) Vsψ graphs enable us to study coupling variations along the same and different isoelectronic sequences.The Z-dependence of the ground intervals 4s2 4p4 have been studied theoretically for the first time. The level values are represented, within less than 0.2% error, by semi-empirical formulae having 3–5 adjusted parameters and are based on data obtained from laboratory observations. The results provide means for checking laboratory and astrophycial identifications and measurements. 相似文献
15.
团簇LaO的理论研究 总被引:3,自引:3,他引:0
采用密度泛函理论研究LaO团簇体系。中性分子LaO的基态是两重态(2Σ),阴离子LaO-和阳离子LaO 的基态都是单重态(1Σ)。使用不同的方法计算团簇LaO的电子亲和能和电离能。计算结果表明用BLYP方法和弥散极化基组计算结果和实验数据吻合较好。用含时密度泛函理论计算团簇LaO的低能激发态,从理论上归属LaO-的光电子能谱的谱峰和LaO的吸收光谱的谱峰。计算得到与实验一致的结果。 相似文献
16.
17.
《Optics Communications》1986,57(5):350-354
A theoretical and computational study is presented of the soliton laser recently constructed by Mollenauer and Stolen. In particular, the role played by the optical fibre in determining the properties of the optical pulses is analysed in detail. 相似文献
18.
We present a robust analysis of the spectral fluctuations exhibited by the light meson spectrum. This analysis provides information about the degree of chaos in light mesons and may be useful to get some insight on the underlying interactions. Our analysis unveils that the statistical properties of the light meson spectrum are close, but not exactly equal, to those of chaotic systems. In addition, we have analyzed several theoretical spectra including the latest lattice QCD calculation. With a single exception, their statistical properties are close to those of a generic integrable system, and thus incompatible with the experimental spectrum. 相似文献
19.
Maria Chiara Aversa Anna Barattucci Paola Bonaccorsi Alessandro Contini 《Journal of Physical Organic Chemistry》2009,22(11):1048-1057
The reaction of benzenesulfenic acid, generated in situ by thermal decomposition of 3‐(phenylsulfinyl)propanenitrile, with monosubstituted acetylenes was experimentally and theoretically investigated at the DFT level using the MPW1B95 density functional. A computational model based on the Hard Soft Acid Base (HSAB) principle was evaluated for its ability to qualitatively and quantitatively predict the regioselectivity, while kinetics and thermodynamics of the reaction were studied through the analysis of the reaction paths leading to the possible regioisomers. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
20.
G. N. Ten O. E. Glukhova M. M. Slepchenkov N. E. Shcherbakova V. I. Baranov 《Optics and Spectroscopy》2016,121(4):599-606
Fluorescence spectra of two long-wavelength electron transitions S0 ← 1Lb and S0 ← 1La in uncharged and zwitterionic forms of L-tryptophan (Trp) in aqueous solution and in the complex of Trp with water molecule were calculated using the Frank–Condon approximation. Geometric parameters of Trp in electronically excited states were determined, and the vibrational structure of vibronic spectra was analyzed. It was shown that the relative position of structural fragments of alanine (R-Ala) and indole (R-In) could have a determining effect on the fluorescence and formation of the vibrational structure of electronic spectra. The increase of the rotation angle between the R-Ala and R-In, which depends on the Trp environment, results in the Trp fluorescence originating only from the singlet excited state 1La. 相似文献