A New Expression for Nuclear Rotational Spectra

A new formula, which is derived from a deformed rotor model for describing nuclear rotational spectra, is analyzed. The ground band of most even-even rare-earth and actinide nuclei are accurately reproduced using a damped nonlinear least-square fitting procedure for determining parameters of the theory. The results show that energy spectra obtained from a deformed rotor model are more accurate than those from a three-parameter formula based on perturbation theory.     

Bohr-Mottelson转动谱公式参数之间的新关系式

在利用Harris两参数公式研究Bohr-Mottelson转动谱公式参数之间的关系的基础上,改用Harris三参数公式,并由此提出了Bohr-Mottelson转动谱公式参数之间的新关系式,进而用I(I+1)四参数展开式计算了A～60,80,130,140,150,190区超形变偶偶核的基带和锕系和稀土区正常形变核基带,讨论了参数之间的关系,发现新关系式与实验较好地符合.     

Test of Trace Formulas for Spectra of Superconducting Microwave Billiards

Experimental tests of various trace formulas, which in general relate the density of states for a given quantum mechanical system to the properties of the periodic orbits of its classical counterpart, for spectra of superconducting microwave billiards of varying chaoticity are reviewed by way of examples. For a two-dimensional Bunimovich stadium billiard the application of Gutzwiller's trace formula is shown to yield correctly locations and strengths of the peaks in the Fourier transformed quantum spectrum in terms of the shortest unstable classical periodic orbits. Furthermore, in two-dimensional billiards of the Limaçon family the transition from regular to chaotic dynamics is studied in terms of a recently derived general trace formula by Ullmo, Grinberg and Tomsovic. Finally, some salient features of wave dynamical chaos in a fully chaotic three-dimensional Sinai microwave billiard are discussed. Here the reconstruction of the spectrum is not as straightforward as in the two-dimensional cases and a modified trace formula as suggested by Balian and Duplantier will have eventually to be applied.     

SUq(2) Analysis of Nuclear Rotational Spectra

The validity of the quantum group SU_q(2) expression for the nuclear rotational spectrum is investigated thoroughly.Analyses (including the Mallmann plots,the relations for the I(I+1) expansion coefficients,energy spectra,etc.)definitely display a systematical deviation of the SU_q(2) prediction from the experimental data available for the even-even rare-earth and actinide nuclei.Only within a limited range of angular momentum the SU_q(2) expression is suitable for rotational spectra.A significant angular momentum dependence of q-deformation parameter is found.The q-deformation is derectly related to the nuclear softness.     

乙基苯胺的转动光谱及分子结构

本文使用傅里叶变换微波谱仪研究了乙基苯胺类物质(邻乙基苯胺,间乙基苯胺,对乙基苯胺)的分子结构. 由于此类分子含氮原子(I¹⁴N=1),因此跃迁谱线中都呈现出核四级裂分. 通过比较实验测定得到的分子结构,可总结苯胺环上不同位置乙基的取代对氨基及分子整体结构的影响.     

Rotational Spectra of Argon Acetone: A Two-Top Internally Rotating Complex

The rotational spectra of the argon acetone weakly bound complex was studied by pulsed jet Fabry-Perot Fourier transform microwave spectroscopy. Over 500 transitions of the complex were measured between 5.5 and 26 GHz from J=2-1 to J=12-11. The two methyl groups undergo hindered internal rotation resulting in four or five internal rotation states. The microwave transitions are within these states, resulting in a splitting of each rotational transition into four and sometimes five distinct transitions. The three-fold barrier to internal rotation is determined to be 260 cm⁻¹, 2% less than the 266 cm⁻¹ barrier in acetone itself. The structure of the complex has the argon atom above the heavy atom plane of the acetone, 3.52 Å from the CO bond and approximately in the C_s plane, which is perpendicular to the CCC plane of acetone.     

Anomalous Rotational Resonance Spectra in Magic-Angle Spinning NMR

Magic-angle spinning NMR spectra of samples containing dilute spin-1/2 pairs display broadenings or splittings when a rotational resonance condition is satisfied, meaning that a small integer multiple of the spinning frequency matches the difference in the two isotropic shift frequencies. We show experimental rotational resonance NMR spectra of a 13C2-labeled retinal which are in qualitative disagreement with existing theory. We propose an explanation of these anomalous rotational spectra involving residual heteronuclear couplings between the 13C nuclei and the neighboring 1H nuclei. These couplings strongly influence the rotational resonance 13C spectrum, despite the presence of a strong radiofrequency decoupling field at the 1H Larmor frequency. We model the residual heteronuclear couplings by differential transverse relaxation of the 13C single-quantum coherences. We present a superoperator theory of the phenomenon and describe a numerical algorithm for rapid Liouville space simulations in periodic systems. Good agreement with experimental results is obtained by using a biexponential transverse relaxation model for each spin site.     

Rotational Spectra of XeH and Its Isotopic Species

Frequencies of rotational transitions of XeH⁺ and its isotopic species were measured in the 1–5 THz region with a highprecision far-infrared spectrometer using a tunable radiation source. Measured frequencies were analyzed together with previous microwave and infrared measurements to refine mass-independent Dunham parameters.     

Pure Rotational Raman Spectra of Vapor Phase Methanols

Abstract

The rotational Raman spectra of four vapor phase isotopic methanols, CH₃OH, CH₃OD, CD₃OH and CD₃OD, have been reported for the first time in the wavenumber regions from 5 to 100–120 cm^?1. The major parts of the spectra consist of bands equispaced at 3.19, 3.04, 2.56 and 2.46 cm^?1 intervals, respectively, and have been interpreted as the pure rotational S-branch transitions.     

The Pure Rotational Spectra of AuCl and AuBr

The pure rotational spectra of AuCl and AuBr have been measured in the v = 0 and 1 (also for v = 2 for Au(35)Cl) vibrational states in the 5-22 GHz spectral region using a cavity pulsed-jet Fourier transform microwave spectrometer. The molecules were prepared by ablating Au metal in the presence of Cl(2) or Br(2) entrained in the Ar or Ne backing gas of the jet. The equilibrium internuclear distances r(e) have been determined along with estimates of the harmonic vibration frequencies and the dissociation energies. The ionic characters of the AuCl and AuBr bonds have been estimated from the halogen nuclear quadrupole-coupling constants to be i(c) approximately 38%. The gold nuclear quadrupole coupling constants change appreciably from AuF to AuCl to AuBr (including a sign change), indicating substantial differences in their electronic structures at Au; these variations could not be accounted for with a simple Townes-Dailey calculation. Copyright 2000 Academic Press.     

Measurement of Rotational Temperature by Simulated Molecular Spectra

The measurement of temperature of heavy particles in a thermal plasma is based on the comparison of experimental rotational spectrum obtained by optical emission Spectroscopy and synthetic spectra calculated for different temperatures. The calculation principle of the synthetic spectra is detailed as well as the temperature accuracy obtained. This method is used to measure the temperature of an Ar-CO₂ mixture plasma produced in a wall stabilized arc with molecular spectra of C₂ (Swan system) and CN (violet system).     

Rotational Spectra of Conformers and Isotopomers of 1-Hydroxynaphthalene

The rotational spectra of cis- and trans-1-hydroxynaphthalene and trans-1-DO-naphthalene have been recorded between 6 and 18 GHz using a pulsed microwave spectrometer. Most of the transitions detected are a type; hyperfine splittings from the electric quadrupole interaction were observed for some transitions of the deuterated isotopomer. The frequencies were well modeled with an S-reduced asymmetric rotor Hamiltonian. The rotational constants were determined much more accurately than previously. In addition, the quartic centrifugal distortion parameters were determined for the first time. Their values were very small, consistent with the rigid framework of this aromatic molecule. Theoretical calculations were carried out to support the assignment of the two forms to the cis and trans conformers. These calculations suggested that the cis conformer is slightly nonplanar in its equilibrium configuration, a property which is not inconsistent with its rotational constants. Copyright 1999 Academic Press.     

Isotopic Study of Rotational Spectra of the Ar-Acetylene Complex

Rotational spectra of the weakly bound complex Ar-acetylene were measured using a Fourier transform microwave spectrometer. Eight additional transitions of the normal isotopomer were detected, following the earlier radiofrequency and microwave investigations [R. L. DeLeon and J. S. Muenter, J. Chem. Phys. 72, 6020-6023 (1980); Y. Ohshima, M. Iida, and Y. Endo, Chem. Phys. Lett. 161, 202-206 (1989)]. Spectra of four minor isotopomers, namely Ar-DCCD, Ar-H(13)C(13)CH, Ar-DCCH, and Ar-H(13)C(12)CH, were newly assigned and analyzed. A semirigid rotor model was employed to obtain the rotational and centrifugal distortion constants, which were in turn used to extract structural information about the complex. The unusually large standard deviations of the spectroscopic fits are indicators of large-amplitude internal motions of the acetylene subunit. Separate fits of the individual K-stacks yielded lower standard deviations, and their results were used to interpret some of the unusual spectroscopic observations. Copyright 2001 Academic Press.     

A Comprehensive Study on Infrared Spectra of 2-Hydroxyxanthone

A study on the IR spectra of 2-hydroxyxanthone that was both experimental and theoretical was carried out in this work. The optimized structure and related spectral parameters were obtained by using the Becke-3-Lee-Yang-Parr (B3LYP) method with the 6-31G* and 6-311G** basis sets. The corresponding geometrical parameters were compared with each other. Detailed assignments of the vibration frequencies were performed. The agreement between the scaled theoretical frequencies and the observed frequencies was found to be quite good. Also, the calculation accuracies of the two basis sets are close.     

八种新型除草剂分子的拉曼光谱研究

合成了八种新型含α-氨基膦酸酯的嘧啶水杨酸类除草剂, 用激光显微拉曼光谱对其进行了表征, 对谱图进行了归属。此外还测试了这八个化合物的除草活性, 对此类除草剂的实际应用提供了实验数据。     

Automated Technique for Identifying Experimental Vibrational–Rotational Molecular Spectra Based on Variational Calculations

We describe a technique for automated identification of experimental vibrational–rotational molecular spectra, which is based on variational calculations. The proposed technique is used to analyze the experimental spectra of triatomic molecules H₂O and HDO. This technique significantly accelerates processing and analysis of experimental data and drastically improves accuracy and quality of the results obtained. The possibility of applying this technique for analyzing spectra of other polyatomic molecules is discussed.     

一种标定新方法在FTIR定量分析中的应用

利用傅里叶变换红外(FTIR)光谱技术可以对气体组分的浓度进行连续的在线定量分析。在定量分析过程中,对FTIR进行标定是非常重要的环节之一,直接关系到定量分析是否可以进行和定量分析的精度。本文提出了一种新的标定方法(称之为“积分法”),以CO、HCI和水蒸气为例完成的实验结果表明：这一方法与传统方法(标气法)相比具有许多优点,准确性和稳定性都很好;尤为重要的是,对于传统方法无法解决的常温下为液态的气体物质的标定问题,利用这一新方法可以迎刃而解,而且有很好的精度。