Ab initio方法研究~(40)Ca~(35)Cl分子的自旋轨道耦合效应和跃迁性质

本文研究了~(40)Ca~(35)Cl分子低态的自旋轨道耦合分裂以及获得更精确的光谱常数和更高的激发态.以从头算理论为基础,使用多参考组态相互作用方法获得了该分子的势能曲线和自旋轨道分裂,之后求解径向一维薛定谔方程获得光谱常数.得到了~(40)Ca~(35)Cl分子7个Λ-S低电子态的势能曲线和永久偶极矩,以及A~2Π→~2Σ~+,1~2Δ和C~2Π→~2Σ~+,1~2Δ跃迁的跃迁偶极矩,得到的光谱常数(不管是考虑了自旋轨道耦合(SOC)还是没有考虑SOC)与实验值非常符合,且要好于之前的理论计算结果 .值得注意的是,目前的计算还首次得到了C~2Π→~2Σ+,1~2Δ跃迁的跃迁性质,为之后实验观察~(40)Ca~(35)Cl分子的高激发态光谱和跃迁性质提供有益的理论参考.     

超精细能级中~(133)Cs激发态|6~2P_(3/2)F〉(F=2,3,4,5)原子与理想金属表面间范德瓦尔斯作用系数C_3的估算

利用碱金属原子与理想金属表面间范德瓦尔斯(vd W)作用势和不可约张量方法,计算~(133)Cs激发态|6~2P_(3/2)F〉(F=2,3,4,5)原子超精细结构的C_3系数.数值分别为:4.338 5 k Hz·μm~3、4.361 9 k Hz·μm~3、4.368 0及4.346 7 k Hz·μm~3.与其它理论数据和实验数据比较,结果表明本文所得到的~(133)Cs激发态|6~2P_(3/2)F〉(F=2,3,4,5)原子的C_3数值是可靠的.     

单氯化锶分子低激发态的光谱及跃迁特性

利用Davidson修正的内收缩多参考组态相互作用(ic-MRCI+Q)方法,结合相对论有效芯赝势基(augcc-pV5Z-PP)作为Sr原子和相关一致五重基aug-cc-pV5Z为Cl原子的计算基组,优化计算了单氯化锶(Sr~(35)Cl)分子14个低激发电子态的势能曲线和跃迁偶极矩.为了获得更加精确的光谱参数,计算中同时引入核价电子相关和相对论效应修正势能曲线.利用LEVEL 8.0程序拟合修正的势能曲线,得到相应电子态的光谱常数、振动能级和分子常数等光谱性质,结果与近来的已获得的理论计算和实验值符合得较好,同时给出了Franck-Condon因子和辐射寿命等跃迁性质.这些精确的光谱跃迁特性可为进一步构建Sr~(35)Cl分子激光冷却方案提供理论支持.     

S_2O激发态(~1A′)振动光谱及势能面的一种代数研究(英文)

利用代数方法研究了非对称弯曲三原子分子S_2O分子处于(?)~1A′电子态的能谱及其稳定构型下的势能面,通过对30条光谱数据的拟和得到的rms误差为2.40 cm~(-1)。结果表明,利用此代数Hamiltonian很好的实现了能级再现,它预测了振动总量子数达到20的全部振动能级,同时我们计算了分子的解离能与力常数。通过与实验值比较证明了这种方法在计算这类分子的有效性。     

∧N相互作用与超核∧_(40)~Ca

对超核_A~(40)Ca两个主要置换态的能级位置、能量差以及以ΛN相互作用诸参数对上述能级位置和能量差的影响进行了计算和分析.用较严格的扭曲波冲量近似对产生超核_A~(40)Ca的(K~-,π~-)反应截面进行了计算,分析了ΛN相互作用各成分对零度反应截面的影响.结果表明,作者以前用于分析1p壳层超核的ΛN相互作用基本上适用于描述中重超核_A~(40)Ca的结构和相关的奇异交换反应,只是有心项强度参数需由0.99减至0.78.     

脉冲激光微扰增强双共振光谱对钠分子4~3∑_g~ 态的新实验观测(英文)

用微扰增强双共振对钠分子4~3∑_g~ 态33900～35200 cm~(-1)的65个振转能级进行了实验观测。以往用连续激光双共振方法只看到低振动能级,用脉冲激光双共振和检测解离产物的方法只观测到高振动能级。获得的新数据填补了以往数据的空缺。综合v=0～31能级所有数据,拟合出一套分子常数,计算出RKR势能曲线。主要分子常数为：T_e=32127.090 cm~(-1),ω_e=121.1099(0.20720)cm~(-1),B_e=0.116287(0.0002300)cm~(-1),Re=3.551 (?)。还对J. Chem. Phys.108,7707 (1998)中RKR势能曲线的一个错误进行了纠正。     

Observation of ~1S_0→~3P_0 Transition of a ~(40)Ca~+-~(27)Al~+ Quantum Logic Clock

We report the realization of quantum logic spectroscopy on the ~1S_0→~3P_0 clock transition of a single ~(27)Al~+ ion. This ion is trapped together with a~(40)Ca~+ ion in a linear Paul trap, coupled by Coulomb repulsion, which provides sympathetic Doppler laser cooling and also the means for internal state detection of the clock state of the ~(27)Al~+ ion. A repetitive quantum nondemolition measurement is performed to improve the fidelity of state detection. These techniques are applied to obtain clock spectroscopy at approximately 45 Hz. We also perform the preliminary locking on the ~1S_0→~3P_0 clock transition. Our work is a fundamental step that is necessary toward obtaining an ultra-precision quantum logic clock based on ~(40)Ca~+-~(27)Al~+ ions.     

用无波函数微扰论计算双原子分子振动能级

本文利用一种新的近似计算方法—无波函数微扰论计算双原子分子振动能级,文中不仅推算出了双原子分子的非谐振动能级理论公式。而且还用它对HCL~(35)分子的振动能级做了具体的计算,通过选取适当的势能参数,理论计算值与实验结果符合得很好.     

NO分子的基态(X~2П)和激发态(a~4П and B~2П)光谱常量和振动能级的计算(英文)

本文使用完全活性空间自洽场/多组态相互作用(CASSCF/MRCI)理论,以cc-pVDZ为基组,计算了NO分子基态(X2Π)和激发态(a4ПandB2П)的平衡结构和单点能扫描曲线.采用最小二乘法拟合了Murrell-Sorbie函数,得到了NO分子的解析势能曲线,并利用Rydberg-Klein-Rees方法,计算得到的NO分子相应态的谐振频率和其它的光谱数据(ωe、αe、ωeχe、βe)与实验值十分一致,和其它理论计算方法进行比较,发现该方法有更好的准确性.以得到的解析势能函数为基础,求解NO分子核运动的一维径向Schrdinger方程,获得了更高振动态的振动能级.     

边限振荡器型核四极矩共振(NQR)谱仪及其对固态样品中~(35)Cl和~(37)Cl的探测

本文介绍一种边限振荡器型核四极矩共振(NQR)谱仪,并给出了它对氯酸钾KClO_3、氯酸钠NaClO_3、氯化钠NaCl等固态化合物中氯的同位素~(35)Cl和~(37)Cl的NQR谱实测结果。在室温下该谱仪对~(35)Cl的NQR频率测量精度约5×10(-6)。信噪比S/N≥80。在77K到393K温区测量了多晶KClO_3样品中~(35)Cl的NOR频率和温度的关系。     

采用ICP-MS/MS准确测定食品中钙和氯

建立利用电感耦合等离子体串联质谱测定食品中钙和氯的分析方法。针对Ca的高丰度同位素40Ca受到来自等离子气40Ar的干扰,35Cl受到来自16O18OH的严重干扰,在MS/MS模式下,利用碰撞/反应池技术,以H₂为反应气,使40Ar+与H₂发生反应,而40Ca+不与H₂发生反应,利用H₂原位质量法消除40Ar+对40Ca+的干扰;而35Cl+则能与H₂发生质量转移反应生成H₂35Cl+,通过测定H₂35Cl+消除16O18OH+对35Cl+的干扰。Ca和Cl在0.0~100.0 μg·L-1的浓度范围内线性关系良好,线性相关系数（R2）≥0.999 9,Ca和Cl的检出限分别为0.061和2.32 μg·L-1。采用系列国家标准物质验证了对方法的准确性和精密度,其测定结果与标准参考物质的认定值基本一致,表明方法的准确性好、精密度高。所建立的新方法可实现食品中钙和氯的准确测定。     

Beam maser measurements of hyperfine structure in chloroacetylene-d

The J = 1-0 transitions in ³⁵ClCCD were measured using a beam maser spectrometer giving a molecular resonance linewidth of 3 kHz (FWHM). Analysis of the data yielded quadrupole coupling strengths eqQ(D) = 208.5 ± 1.5, eqQ(³⁵Cl)= 79 739.5 ± 1 kHz and the ³⁵Cl spinrotation interaction strength C(Cl) 1.3 ± 0.1 kHz. The rotational constant obtained is B = 5 186 973.9 ± 1.0 kHz. The accuracy of measured molecular parameters is improved by a factor of 20 or better.     

Anomalous H/D isotope effect on 35Cl NQR frequencies in piperidinium p-chlorobenzoate

Anomalous isotope effects were detected in the ³⁵Cl nuclear quadrupole resonance (NQR) frequency of piperidinium p-chlrobenzoate (C₅H₁₀NH· ClC₆H₄COOH) by deuteration of hydrogen atoms. The atoms were determined to form two kinds of N–H···O type H-bonds in the crystal structure. Large frequency shifts of the ³⁵Cl resonance lines reaching 288 kHz at 77 K and 278 kHz at room temperature were caused upon deuteration, in spite of the fact that the Cl atoms in the molecule do not form hydrogen bonds in the crystal. Results of single crystal X-ray diffraction measurements and density-functional-theorem calculations suggest that a dihedral-angle change of 1.8° between benzene and the piperidine ring contributes to ³⁵Cl NQR anomalous frequency shifts.     

Microwave spectrum and Structure of Benzenesulphonyl chloride

The microwave spectrum has been investigated for the molecule of Benzenesulphonyl chloride within the 8–18 Ghz frequency region. Several a and b type bands corresponding to the Cl³⁵ and Cl³⁷ Isotopes were observed and assigned.

We have also used the CNDO/2 method in order to estimate some molecular parameters and the dipole moment. The theoretical calculation and the experimental data have been joined to derive a reliable structure of the molecule concluding that the Cl is located on the plane of the benzene ring.     

35Cl quadrupolar constants obtained by solid-state NMR: study of chlorinated Al-O-P clusters,involving OH...Cl hydrogen bonds

Simulation of static and MAS NMR spectra obtained at high field (B(0) = 14.08 T) and high spinning frequency (up to nu(rot) = 22 kHz) allows the determination of 35Cl quadrupolar parameters for various cubane-shaped, cage-like and cyclic Al-O-P clusters; the role of OH...Cl contacts is emphasized.     

Resonances of stretched states in open shell nuclei

-Form factors of 1?ω maximal spin resonances are obtained in the version “particle core coupling” of multiparticle shell model for the nuclei ²⁴Mg, ²⁶Mg, ²⁸Si, ⁴⁰Ca, ⁴²Ca, ⁴⁴Ca. Wave functions of excited states are calculated using information on the spectroscopy of direct reactions. Comparison with a cross section of (e, e′) reactions showed that the theoretical calculation is in good agreement with existing experimental data. Fragmentation of M6 resonance force in ⁴⁰Ca into 22 peaks is shown.     

Theoretical analysis of mass distribution of quasifission for 238U-induced reactions

Fragment mass distributions of quasifission induced by ²³⁸U on ¹⁶O, ²⁶Mg, ³²S, ³⁵Cl, ⁴⁰Ca and ⁶⁵Zn targets at several bombarding energies have been calculated with the two-step model. The experimental data are reproduced consistently, and the mechanism of the distribution shape is also analyzed by investigating the different incident channels.     

Zero-motion correlations in high-energy proton elastic scattering on40Ca with noneikonal nucleon-nucleon amplitude

Using a noneikonal expression for the two-body scattering amplitude, consistent with the proton-nucleon scattering data, the cross-section of the 1.04 GeV-proton elastic scattering on⁴⁰Ca is calculated by the Glauber-Sitenko theoretical scheme in the framework of the coherent density fluctuation model (CDFM) as well as of the independent-particle model (IPM). It is shown that the use of the noneikonal amplitude in the CDFM calculation improves the agreement with the experimental data especially at larger scattering angles in contrast to the case of the independent-particle model. To that end a decisive role play the zero-motion flucton correlations taken into account in the CDFM.     

Ultrasound-ionic liquid enhanced enzymatic and acid hydrolysis of biomass cellulose

The purpose of this paper was to investigate the effect of ultrasound-ionic liquid (IL) pretreatment on the enzymatic and acid hydrolysis of the sugarcane bagasse and wheat straw. The lignocellulosic biomass was dissociated in ILs ([Bmim]Cl and [Bmim]AOC) aided by ultrasound waves. Sonication was performed at different frequencies (20, 28, 35, 40, and 50 kHz), a power of 100 W, a time of 30 min and a temperature of 80 °C. The changes in the structure and crystallinity of the cellulose were studied by Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). The amounts of the total reducing sugars, glucose, cellobiose, xylose and arabinose in the hydrolysates were determined. The results of FT-IR, XRD and TGA revealed that the structure of cellulose of both biomass samples remained intact after the pretreatment, but the crystallinity decreased. The enzymatic and acid hydrolysis of the biomass samples pretreated with the ultrasound-IL result in higher yields of the reducing sugars compared with the IL-pretreated sample. Enzymatic hydrolysis of bagasse and wheat straw pretreated with [Bmim]Cl-ultrasound resulted in maximal yields of glucose at 20 kHz (40.32% and 53.17%) and acid hydrolysis resulted in maximal yields of glucose at 40 kHz (33.32% and 48.07%). Enzymatic hydrolysis of bagasse and wheat straw pretreated with [Bmim]OAc-ultrasound show maximal yields of glucose at 28 kHz and acid hydrolysis at 50 kHz. Combination of ultrasound with [Bmim]OAc is more effective than [Bmim]Cl in terms of the yields of reducing sugar.     

Reflection and transmission at normal incidence onto air-saturated porous materials and direct measurements based on parametric demodulated ultrasonic waves

The present work is related to the characterization of air-saturated porous media by using parametric demodulated ultrasonic waves. One uses two different powerful ultrasonic emitters working either at 47 kHz or at 162 kHz which are electronically amplitude modulated over the 200 Hz-4 kHz or 2 kHz-40 kHz bandwidths respectively. The demodulation process takes place in air, due to its nonlinearity enabling to generate audio range acoustical waves or alternatively low frequency ultrasonic waves which can be used to characterize porous materials in the reflection configuration at normal incidence. Some appropriate theoretical calculations are introduced for three configurations of interest, i.e. a porous slab, a porous layer mounted onto a rigid plate, and a porous half space, in the case of the equivalent-fluid model. Comparisons between theoretical modeling and experimental data are provided and prospective industrial applications are discussed.