He-H_2S复合物的六维从头算势能面和束缚态（英文）

采用[CCSD(T)]-F12a/aug-cc-pVTZ方法,同时在基组中引入中心键函数(3s3p2d1f1g)构建了He-H_2S复合物的高精度六维势能面.除分子间振动坐标,同时考虑了H_2S分子内的v_1对称伸缩振动Q_1正则模、v_2弯曲振动Q_2正则模和v_3反对称伸缩振动Q_3正则模三种振动模式.将计算得到的六维势能面在Q_1,Q_2和Q_3方向上分别做积分得到H_2S单体分别处于振动基态、v_2和v_3激发态下的He-H_2S的三个振动平均势能面.计算结果表明,每个平均势能面都有一个T形全局极小值、一个平面局部极小值、两个平面内鞍点和一个平面外鞍点.全局极小值的几何构型位于R=3.46 A,θ=109.9~°和_(φ=)0.0°,势阱深度为35.301 cm-1.在径向部分采用离散变量表象法和角度部分采用有限基组表象法并结合Lanczos循环算法计算了He-H_2S的振转能级和束缚态.计算发现He-(par a-H_2S)在H_2S的_(v_2)和v_3区域的带心位移分别为0.025 cm~(-1)和0.031 cm~(-1),而He-(ortho-H_2S)的带心位移分别为0.041 cm~(-1)和0.060 cm~(-1),都表现为蓝移.     

He-LiH的从头算势能面

采用超分子CCSD(T)方法和由键函数3s3p2d1f组成的大基组,计算得到了He-LiH体系的全程势能面.计算结果表明该势能面存在2个势阱:较深的势阱在Rm=4.25a0,阱深为177.53?cm-1,对应于线性He-LiH构型;较浅的势阱在Rm=10.0a0处,阱深仅为9.88?cm-1,对应于线性He-HLi构型.     

S2O分子的局域势能面和振动光谱的解析

用MRCISD和MRPT2计算了S2O分子的局域势能面,对计算点完成了力场多项式拟合和振动组态相互作用的计算.然后,对其基态(X1A')和激发态(C1A')的振动模式和振动光谱进行分析.通过调节力常数,势能面得到进一步改进.与已有的实验能谱数据进行比较,基态与激发态的均方差分别为38.52cm-1和6.44cm-1.     

He-LiH的从头算势能面

采用超分子单双迭代耦合簇理论CCSD(T)方法和由键函数3s3p2d1f组成的大基组,计算得到了He-LiH体系的全程势能面.计算结果表明该势能面存在2个势阱:较深的势阱在Rm=0.225 nm处,阱深为177.53 cm-1,对应于线性He-LiH构型;较浅的势阱在Rm=0.529 nm处,阱深仅为9.88 cm-1,对应于线性He-HLi构型.     

Kr-CS2体系势能面及束缚态能级的理论研究

本文采用单双迭代(包括非迭代三重激发)耦合簇CCSD(T)方法,对C、S原子采用aug-cc-PVTZ基组,对Kr原子采用cc-PVTZ –DK基组,并且加上中心键函数(3s3p2d2f1g),计算得到Kr-CS2体系的势能面。该势能面为T型结构,存在一个全局极小值和两个等价的局域极小值。全局极小值位于R =7.05 a0,θ= 90°处,势能值为-396.194 cm-1。两个局域极小值分别位于R = 10.15 a0,θ= 0°和180°处,势能为-243.647 cm-1。利用该势能面,通过数值求解相应的薛定谔方程,计算得出体系J≤10的束缚态能级及微波谱跃迁频率,并通过跃迁频率拟合得到相应的光谱常数。     

Ar-CS2体系势能面和微波谱的从头算研究

本文采用单双迭代(包括非迭代三重激发)耦合簇CCSD(T)方法,使用了扩展的相关一致基组aug-cc-pVTZ,并且加入了(3s3p2d2f1g)中心键函数,计算得到Ar-CS2体系的势能面。结果显示势能面有一个全局极小值和两个等价的局域极小值,为T型结构。全局极小值位于R = 6.936 a0,θ=90º 处,势能为-273.89 cm-1 。两个局域极小值分别位于θ=0º 和θ=180º ,R = 9.960 a0 的位置上,势能为-165.391 cm-1。在该势能面的基础上,通过求解体系的薛定谔方程,计算出体系( J≤10)的束缚态能级及微波跃迁频率,拟合得到体系的光谱常数,与实验结果吻合较好。     

Be-CO体系的相互作用势和光谱预测（英文）

采用单双迭代(包括非迭代三重激发)耦合簇CCSD(T)理论方法和大基组,计算Be-CO体系的相互作用势,得到该体系势能面的解析表达.发现在R_e=8.29a0和θ_e=115.42°处存在的一个全局极小势阱,阱深-69.21cm~(-1),势能面呈现较弱的各项异性.根据势能面,计算了体系的束缚态能级和其光谱常数.     

PdH、PdH2分子的结构与势能函数

用相对论有效原子实势(SDD)和密度泛函(B3LYP)方法对PdH和PdH2体系的结构进行了优化,计算表明:PdH分子的几何构型为C∞v,其基态为X2∑+态,键长R=0.154 11 nm,离解能为De=2.511 0eV,谐振频率ωe=2 156.226 9 cm-1,并拟合得到Murrell-Sorbie势能函数;PdH2分子稳态为C2y构型,电子组态为1A1,平衡核间距RPdH=0.151 73 nm,键角∠HPdH=72.373 3°,基态简正振动频率:对称伸缩振动频率v1(b2)=2 104.369 6 cm-1、弯曲振动频率v2(a1)=528.742 6 cm-1、反对称伸缩振动频率v3(a1)=2 208.649 0 cm-1,离解能De=5.318 56 eV.在此基础上,用Murrell-Sorbie函数和多体展式理论导出PdH(C∞v,X2∑+)、PdH2(C2v,1A1)分子的解析势能函数.其等值势能面图准确地再现了PdH2分子的结构特征和离解能,由此讨论了Pd+H2分子反应的势能面静态特征.     

Kr-CS_2体系势能面及束缚态能级的理论研究

本文采用单双迭代(包括非迭代三重激发)耦合簇CCSD(T)方法,对C、S原子采用aug-ccPVTZ基组,对Kr原子采用cc-PVTZ-DK基组,并且加上中心键函数(3s3p2d2f1g),计算得到Kr-CS_2体系的势能面.该势能面为T型结构,存在一个全局极小值和两个等价的局域极小值.全局极小值位于R=7.05 a0,θ=90°处,势能值为-396.194 cm~(-1).两个局域极小值分别位于R=10.15 a0,θ=0°和180°处,势能为-243.647 cm~(-1).利用该势能面,通过数值求解相应的薛定谔方程,计算得出体系J≤10的束缚态能级及微波谱跃迁频率,并通过跃迁频率拟合得到相应的光谱常数.     

AuZn和AuAl分子基态与低激发态的势能函数与热力学性质

用密度泛函理论B3LYP方法计算研究AuZn和AuAl分子基态与低激发态的结构与势能函数,导出分子的光谱数据.结果表明,AuZn和AuAl分子基态分别为X²Σ和X¹Σ,基态与低激发态的势能函数均可用Murrell-Sorbie函数来表达.AuZn分子低激发态a⁴Σ的绝热激发能为43529kJ/mol,AuAl分子低激发态a³Σ的绝热激发能为19991kJ/mol.计算固体AuZn和AuAl的内能和熵时,近似以气体分子的电子能和振动能代替固体分子的内能,用电子熵和振动熵代替固体分子的熵.在此近似下,计算得到AuZn和AuAl基态与低激发态固态分子生成反应热力学性质与温度的关系. 关键词： AuZn和AuAl B3LYP 热力学性质 势能函数     

Submillimeter-Wave Spectroscopy of CO in the a(3)Pi State

Submillimeter-wave absorption spectrum of CO in electronically excited a(3)Pi state was observed in the 540-830 GHz region by using a phase-locked BWO spectrometer. New rotational transitions up to J = 9-8 in the vibrational excited states up to v = 5 were analyzed accompanied with previous observations in the RF and millimeter-wave regions. A multivibrational states fit among a' (3)Sigma(+) (v = 0-3) and a(3)Pi (v = 0-7) states was performed in order to analyze overall perturbation between the a(3)Pi and a' (3)Sigma(+) states. As a result, the deperturbed rotational parameters were derived precisely to improve the RKR potential. Copyright 2000 Academic Press.     

Photoelectron and electron impact spectrum of HCN

The electronic structures of HCN and DCN have been determined by examining high resolution He(I) photelectron spectra of HCN and DCN, He(II) photoelectron spectrum of HCN, and the electron impact energy loss spectra of HCN and DCN. The present investigation supports an earlier assignment of the orbital sequence in HCN. New vibrational data are presented and the Rydberg series and valence transitions are reinvestigated. The adiabatic ionization energies for the 1π and 5σ orbitals in HCN are found to be 13.607 ± 0.002 eV and 14.011 ± 0.003 eV respectively.As mentioned above the investigation of the Rydberg series indicated that the first IP at 13.607 eV is the 1π ionization and the second IP at 14.011 eV is the 5σ ionization. A comparison of the experimental and theoretical intensity ratio between the two first PES progressions also supports this assignment. It is further supported by the fact that in the second IP the ν₃ vibration frequency is not changed as much as it is in the first IP, which is in agreement with the PES of N₂ and CO. The analysis of the bending vibrations also supports this ordering of the orbitals.The same orbital assignment has recently been proposed by Frost et al.⁵, using a comparison with the HCP photoelectron spectrum. The present paper supports their assignment of orbitals and (00⁰0)-(00⁰0) transitions. There are, however, some disagreements concerning the vibrational analysis. This is probably due to the fact that the HCN spectrum of Frost et al.⁵ revealed less structure than ours. As indicated by Figure 5 there is possibly still more structure to be revealed.     

激光烧蚀Al热原子与CF4反应中C2的形成及其发光光谱研究

脉冲激光烧蚀金属平面铝靶产生的热原子与气相CF4碰撞反应中，在400—600nm之间观测到激发态C2分子的发光光谱，它们可归属为Swan带的d3Πg-a3Πu跃迁中Δv＝２，1，0，-1，-2五个振动序列（v'≤6）.光谱强度分析表明，C2激发态的振动温度达6340K左右.与激光烧蚀Al＋O2反应生成AlO的实验结果以及激光烧蚀Cu＋CF4的光谱比较，对比Al(2P1/2-2S1/2,3944nm）和C2的d—a跃迁（0—0）带带头（5165nm)的飞行时间轮廓，认为激发态的Al(2S1/2)原子通过 关键词： 激光烧蚀 发光光谱 C2分子     

High-temperature infrared spectrum of HCN near 3300 cm−2

The infrared absorption of HCN near the fundamental band at 3311 cm^?1 has been measured at temperatures up to 1200 K. Transitions involving high rotational states (up to J = 62) have been measured. These give an improved value for the sextic centrifugal distortion term H₀. Many hot-band transitions have been observed and assigned to transitions originating in vibrationally excited states up to 4000 cm^?1 above the ground state. These measurements give new data on vibrational states involving moderately high bending quantum numbers and indicate that new terms are needed to fit the ro-vibrational energy levels.     

Experimental Characterization of the Higher Vibrationally Excited States of HCO(+): Determination of omega(2), x(22), g(22), and B(030)

Analyses of high Rydberg series of HCO converging to the (030) vibrational state of the cation establish rovibrational state-detailed thresholds for HCO(+). UV-visible laser double resonance isolates series for assignment. Strongly vertical Rydberg-Rydberg transitions from photoselected N' = 0 and N' = 2 rotational levels of the Sigma(-) Renner-Teller vibronic component of the 3ppi (2)Pi (030) complex define individual series converging to rotational levels, N(+) = 1 through 5 and 3 through 5 of the HCO(+) vibrational states (03(1)0) and (03(3)0), respectively. Extrapolation of autoionizing series locates the positions of these rovibrational states to within +/-0.01 cm(-1). The use of this information combined with precise ionization limits for lower vibrational states determined from earlier Rydberg extrapolations and spectroscopic information available from infrared absorption measurements enables an estimate of the force-field parameters for HCO(+) bending. These parameters include the harmonic bending frequency, omega(2) = 842.57 cm(-1), the vibrational angular momentum splitting constant, g(22) = 3.26 cm(-1), and the diagonal bending anharmonicity, x(22) = -2.53 cm(-1), separated from the off-diagonal contribution, x(12), by reference to ab initio calculations. Results of experiment on the higher vibrationally excited states of HCO(+) are compared with recent theoretical predictions. Copyright 2000 Academic Press.     

Constrained relativistic mean-field approach with fixed configurations

A diabatic (configuration-fixed) constrained approach to calculate the potential energy surface (PES) of the nucleus is developed in the relativistic mean-field model. As an example, the potential energy surfaces of ²⁰⁸Pb obtained from both adiabatic and diabatic constrained approaches are investigated and compared. It is shown that the diabatic constrained approach enables one to decompose the segmented PES obtained in usual adiabatic approaches into separate parts uniquely characterized by different configurations, to follow the evolution of single-particle orbits till the very deformed region, and to obtain several well-defined deformed excited states which can hardly be expected from the adiabatic PESs.     

A new four-dimensional ab initio potential energy surface and predicted infrared spectra for the Ne–CS2 complex

A new four-dimensional (4D) ab initio potential energy surface (PES) for Ne–CS₂ involving the Q₁ and Q₃ normal modes for the ν₁ symmetric stretching vibration and ν₃ antisymmetric stretching vibration of CS₂ is presented. The PES is constructed at the coupled-cluster singles and doubles with noniterative inclusion of connected triples [CCSD(T)]-F12 level with a large basis set including midpoint bond functions. Two vibrationally averaged potentials with CS₂ at the vibrational ground and ν₁ + ν₃ excited states are generated from the 4D potential. Each potential contains a T-shaped global minimum and two equivalent linear local minima. The rovibrational energy levels and bound states are calculated employing radial discrete variable representation/angular finite basis representation and the Lanczos algorithm. In addition, the predicted band origin shift is 0.2514 cm^?1 for Ne–CS₂. The spectroscopic parameters are also predicted.     

First-principles prediction and partial characterization of the vibrational states of water up to dissociation

A new, accurate, global, mass-independent, first-principles potential energy surface (PES) is presented for the ground electronic state of the water molecule. The PES is based on 2200 energy points computed at the all-electron aug-cc-pCV6Z IC-MRCI(8,2) level of electronic structure theory and includes the relativistic one-electron mass-velocity and Darwin corrections. For H₂¹⁶O, the PES has a dissociation energy of D₀ = 41 109 cm⁻¹ and supports 1150 vibrational energy levels up to 41 083 cm⁻¹. The deviation between the computed and the experimentally measured energy levels is below 15 cm⁻¹ for all the states with energies less than 39 000 cm⁻¹. Characterization of approximate vibrational quantum numbers is performed using several techniques: energy decomposition, wave function plots, normal mode distribution, expectation values of the squares of internal coordinates, and perturbing the bending part of the PES. Vibrational normal mode labels, though often not physically meaningful, have been assigned to all the states below 26 500 cm⁻¹ and to many more above it, including some highly excited stretching states all the way to dissociation. Issues to do with calculating vibrational band intensities for the higher-lying states are discussed.     

Fourier Transform Spectroscopy of the A'(1)Pi-X(1)Sigma(+) System of CaO

The A'(1)Pi-X(1)Sigma(+) near-infrared system of CaO was observed for the first time at high resolution using a Fourier transform spectrometer. The A'(1)Pi-X(1)Sigma(+) chemiluminescence was excited in a Ca + N(2)O flame produced in a Broida-type oven. More than 3000 rotational lines, classified into 19 bands involving the A'(1)Pi 0 /= 2) levels with the nearby b(3)Sigma(+) (v-2) levels has been detected. An extended set of A'(1)Pi (v = 0-3) data has been obtained which is suitable for use in a future multistate deperturbation analysis of the a(3)Pi approximately A'(1)Pi approximately b(3)Sigma(+) approximately A(1)Sigma(+) complex of excited states. The new near-infrared spectra of the A'(1)Pi-X(1)Sigma(+) transition of CaO also permits the first direct high-resolution linkage between the orange and green systems and the near-infrared bands. Copyright 2000 Academic Press.     

The two-dimensional anharmonic oscillator: The CCC bending mode of C3O2

Newly observed data on the rotational constants of carbon su?ide in excited vibrational states of the low-wavenumber bending vibration ν₇ have been successfully interpreted in terms of the two-dimensional anharmonic oscillator wavefunctions associated with this vibration. By combining these results with published infrared and Raman spectra the vibrational assignment has been extended and a refined bending potential for ν₇ has been derived: this has a minimum at a bending angle of about 24° at the central C atom, with an energy maximum at the linear configuration some 23 cm^?1 above the minimum. From similar data on the combination and hot bands of ν₇ with ν₄ (1587 cm^?1) and ν₂ (786 cm^?1) the effective ν₇ bending potential has also been determined in the one-quantum excited states of ν₄ and ν₂. The effective ν₇ potential shows significant changes from the ground vibrational state; the central hump in the ν₇ potential surface is increased to about 50 cm^?1 in the v₄ = 1 state, and decreased to about 1 cm^?1 in the v₂ = 1 state. In the light of these results vibrational assignments are suggested for most of the observed bands in the infrared and Raman spectra of C₃O₂.