内层电子相关对NaH分子特征的影响

采用从头计算多参考组态CI方法(MRCI)研究了NaH分子的基电子态的内层电子相关对其分子特征的影响.计算了不同内层电子数目相关情况下的势能曲线,通过解析势能函数拟合,计算出了光谱常数.利用求解分子核运动薜定谔方程的方法,得出了振动能级.通过分析Na原子内层电子与价电子相互作用受H原子核影响的变化,对NaH分子的势能曲线、光谱常数和振动能级等特征量随相关电子数目的变化作了合理的解释.     

B3分子的结构和势能函数

利用从头计算法QCISD/6-311G**确定了B3分子的基电子态,并计算了结构参数.采用原子分子反应静力学原理推导了其离解极限.在此基础上,用多体展式法导出了B3(X2A′1)的解析势能函数,可用于进一步的计算研究.通过势能函数等值图和三维图分析和展示了B3分子的结构特点,并指出由B2到B3分子的最可能途径.     

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.     

B3分子的结构和热能函数

利用从头计算法QCISD／6－311G确定了B3分子的基电子态,并计算了结构参数。采用原子分子反应静力学原理推导了其离解极限。在此基础上,用多体展式法导出了B3（X^2A’1）的解析势能函数,可用于进一步的计算研究。通过势能函数等值图和三维图分析和展求了B3分子的结构特点,并指出由B2到B3分子的最可能途径。     

基于多参考组态方法研究MgI分子激发态的光谱

利用Davidson修正的内收缩多参考组态相互作用（ic-MRCI+Q）方法,结合相关一致全电子基aug-cc-pwCV5Z+DK作为Mg原子和相对论有效芯赝势基（aug-cc-pV5Z-PP）为I原子的计算基组,优化计算MgI分子5个低激发束缚电子态的势能曲线和偶极矩,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LEVEL8.0程序拟合修正的势能曲线,得到光谱常数、振动能级和分子常数等光谱性质,结果与近来的部分理论计算或实验值吻合得较好,提供了更多激发态的光谱性质.为进一步研究MgI分子高激发态的光谱和跃迁特性提供理论支持.     

内层电子相关对NaH分子特征的影响

采用从头计算多参考组态CI方法(MRCI)研究了NaH分子的基电子态的内层电子相关对其分子特征的影响。计算了不同内层电子数目相关情况下的势能曲线，通过解析势能函数拟合，计算出了光谱常数。利用求解分子核运动薜定谔方程的方法，得出了振动能级。通过分析Na原子内层电子与价电子相互作用受H原子核影响的变化，对NaH分子的势能曲线、光谱常数和振动能级等特征量随相关电子数目的变化作了合理的解释。     

多参考组态相互作用方法研究ZnHg低激发态(1Ⅱ,3Ⅱ)的势能曲线和解析势能函数

采用多参考组态相互作用方法计算了ZnHg二聚体两个低激发Ⅱ态(1Ⅱ,3Ⅱ)的原子间相互作用势能曲线.用Murrel-Sorbie函数拟合得到了相应的解析势能函数,并用其计算力常数,进而确定了光谱常数.所得结果与仅有的理论工作进行了比较.基于所得势能曲线,通过解分子中原子核运动的薛定谔方程预测了各电子态的振动能级.     

多参考组态相互作用方法研究ZnHg低激发态(~1∏,~3∏)的势能曲线和解析势能函数

采用多参考组态相互作用方法计算了ZnHg二聚体两个低激发∏态(1∏,3∏)的原子间相互作用势能曲线.用Murrel-Sorbie函数拟合得到了相应的解析势能函数,并用其计算力常数,进而确定了光谱常数.所得结果与仅有的理论工作进行了比较.基于所得势能曲线,通过解分子中原子核运动的薛定谔方程预测了各电子态的振动能级.     

多参考组态相互作用方法研究ZnHg低激发态(1∏，3∏)的势能曲线和解析势能函数

采用多参考组态相互作用方法计算了ZnHg二聚体两个低激发∏态(¹∏，³∏)的原子间相互作用势能曲线. 用Murrel-Sorbie函数拟合得到了相应的解析势能函数，并用其计算力常数，进而确定了光谱常数. 所得结果与仅有的理论工作进行了比较. 基于所得势能曲线，通过解分子中原子核运动的薛定谔方程预测了各电子态的振动能级. 关键词： 势能曲线 解析势能函数 光谱常数 振动能级     

75As32S+和75As34S+离子的光谱常数与分子常数

采用内收缩多参考组态相互作用(MRCI)方法, 结合Dunning系列相关一致基, 分别对⁷⁵As³²S⁺和⁷⁵As³⁴S⁺离子的X³Σ^-和A¹Π电子态的势能曲线进行了计算, 进一步拟合势能曲线, 得到各电子态的光谱常数与分子常数. 首先, 采用MRCI方法结合相关一致基, aug-cc-pV5Z, 对AsS⁺离子的X³Σ^-和A¹Π 电子态进行了计算, 获得相应的势能曲线; 然后, 为进一步提高势能曲线的精度, 对其进行了三种修正计算. 采用Davidson(+Q)方法修正MRCI 方法计算过程中存在的基组大小不一致缺陷; 利用二阶Douglas-Kroll哈密顿近似, 在cc-pVQZ基组水平, 修正了相对论效应对势能曲线的影响; 利用两点能量外推法, 在aug-cc-pVQZ和aug-cc-pV5Z基组水平对各能量点的势能值进行了外推, 得到完全基组极限处的势能曲线. 最后, 利用修正(包括Davidson修正、相对论修正和基组外推)后的势能曲线, 通过Vibrot程序, 求解双原子分子核运动的径向Schrödinger方程, 并进行同位素质量识别, 得到⁷⁵As³²S⁺和⁷⁵As³⁴S⁺离子两个电子态的光谱常数(T_e, R_e, ω_e, ω_ex_e, α_e 和B_e)和分子常数(G(ϒ), B_v, D_v).     

Si2O2 molecule: structure of ground state and the excited properties under different external electric fields

Geometry and vibrational frequencies of the ground state of Si 2 O 2 molecule are studied using density function theory (DFT) at the level of cc-pvtz and 6-311++G.It is found that the optimizing value by B3lyp/cc-pvtz is closer to the experimental data.The excited properties under different external electric fields are also investigated by the time-dependent-DFT method.Transitions from the ground state of Si 2 O 2 molecule to the first singlet state under different external electric fields can take place more easily.The corresponding absorption spectral line is about 360 nm in wavelength and the excitation energy is about 3.4 eV.     

Properties of a Si₂N molecule under an external electric field

In the present work,we adopt the ccsd/6-31g(d) method to optimize the ground state structure and calculate the vibrational frequency of the Si2N molecule.The calculated frequencies accord satisfactorily with the experimental values,which helps confirm the ground state structure of the molecule.In order to find how the external electric field affects the Si2N molecule,we use the density functional method B3P86/6-31g(d) to optimize the ground state structure and the time-dependent density functional theory TDDFT/6-31g(d) to study the absorption spectra,the excitation energies,the oscillator strengths,and the dipole moments of the Si2N molecule under different external electric fields.It is found that the absorption spectra,the excitation energies,the oscillator strengths,and the dipole moments of the Si2N molecule are affected by the external electric field.One of the valuable results is that the absorption spectra of the yellow and the blue-violet light of the Si2N molecule each have a red shift under the electric field.The luminescence mechanism in the visible light region of the Si2N molecule is also investigated and compared with the experimental data.     

Theoretical study of the structure and analytic potential energy function for the ground state of the PO₂ molecule

In this paper, the energy, equilibrium geometry, and harmonic frequency of the ground electronic state of PO2 are computed using the B3LYP, B3P86, CCSD(T), and QCISD(T) methods in conjunction with the 6-311++G(3df, 3pd) and cc-pVTZ basis sets. A comparison between the computational results and the experimental values indicates that the B3P86/6-311++G(3df, 3pd) method can give better energy calculation results for the PO 2 molecule. It is shown that the ground state of the PO2 molecule has C2v symmetry and its ground electronic state is X2 A1 . The equilibrium parameters of the structure are R P O = 0.1465 nm, ∠OPO = 134.96°, and the dissociation energy is Ed = 19.218 eV. The bent vibrational frequency ν 1 = 386 cm-1 , symmetric stretching frequency ν 2 = 1095 cm-1 , and asymmetric stretching frequency ν 3 = 1333 cm-1 are obtained. On the basis of atomic and molecular reaction statics, a reasonable dissociation limit for the ground state of the PO2 molecule is determined. Then the analytic potential energy function of the PO2 molecule is derived using many-body expansion theory. The potential curves correctly reproduce the configurations and the dissociation energy for the PO2 molecule.     

Properties of a Si2N molecule under an external electric field

In the present work,we adopt the ccsd/6-31g（d） method to optimize the ground state structure and calculate the vibrational frequency of the Si2N molecule.The calculated frequencies accord satisfactorily with the experimental values,which helps confirm the ground state structure of the molecule.In order to find how the external electric field affects the Si2N molecule,we use the density functional method B3P86/6-31g（d） to optimize the ground state structure and the time-dependent density functional theory TDDFT/6-31g（d） to study the absorption spectra,the excitation energies,the oscillator strengths,and the dipole moments of the Si2N molecule under different external electric fields.It is found that the absorption spectra,the excitation energies,the oscillator strengths,and the dipole moments of the Si2N molecule are affected by the external electric field.One of the valuable results is that the absorption spectra of the yellow and the blue-violet light of the Si2N molecule each have a red shift under the electric field.The luminescence mechanism in the visible light region of the Si2N molecule is also investigated and compared with the experimental data.     

TiN分子基态(X2Σ)结构和势能函数

应用群论及原子分子反应静力学方法推导了TiN分子基态(X²Σ)的离解极限. 采用不同的密度泛函方法,包括BP86, B3P86, B3LYP, B3PW91, 分别选用不同的基组对TiN分子基态进行结构优化计算.通过比较得出使用BP86方法, 对N原子使用D95V++(d,P)基组和Ti原子使用6-311++G^**基组时,计算得到的平衡几何结构、分子离解能和谐振频率与实验值符合得最好. 并采用最小二乘法拟合改进的Murrell-Sorbie函数得到了相应电子态的完整势能函数. 计算得到的光谱常数与实验光谱数据符合得很好. 关键词： BP86 TiN分子基态 势能函数 光谱常数     

HNO分子基态的结构与解析势能函数研究

应用群论及原子分子反应静力学的方法, 导出了HNO分子基态电子态和合理的离解极限.利用优选出的密度泛函理论B3LYP方法结合6-311G **优化计算了HNO分子基态的平衡结构和谐振频率.计算结果表明基态HNO分子稳定态为C_S构型,电子组态为X¹A',平衡核间距分别为R_H-N=0.1065 nm,R_N-O=0.1200 nm,键角∠H-N-O=108.60°,离解能D_e=15.379 eV.基态简正振动频率分别为:弯曲振动频率ν₁=1575.6351 cm^-1,对称伸缩振动频率ν₂=1673.2890 cm^-1,反对称伸缩振动频率ν₃=2837.7856 cm^-1.在此基础上,应用多体项展式理论导出了基态HNO分子的全空间解析势能函数,该势能函数等值势能图准确再现了HNO分子平衡结构和离解能. 关键词： 势能函数 光谱常数 密度泛函方法     

Spin polarization effect for Tc2 molecule

Density functional method (DFT) (B3p86) of Gaussian98 has been used to optimize the structure of the Tc_2 molecule. The result shows that the ground state for Tc_2 molecule is an 11-multiple state and its electronic configuration is {}^{11}Σ_g^-, which shows the spin polarization effect of Tc_2 molecule of a transition metal element for the first time. Meanwhile, we have not found any spin pollution because the wavefunction of the ground state does not mingle with wavefunctions of higher energy states. So, that the ground state for Tc_2 molecule is an 11-multiple state is indicative of the spin polarization effect of Tc_2 molecule of a transition metal element: that is, there exist 10 parallel spin electrons. The non-conjugated electron is greatest in number. These electrons occupy different spacious tracks, so that the energy of Tc_2 molecule is minimized. It can be concluded that the effect of parallel spin of the Tc_2 molecule is larger than the effect of the conjugated molecule, which is obviously related to the effect of electron d delocalization. In addition, the Murrell--Sorbie potential functions with the parameters for the ground state {}^{11}Σ_g^- and other states of Tc_2 molecule are derived. Dissociation energy D_e for the ground state of T_{c2} molecule is 2.266eV, equilibrium bond length R_e is 0.2841nm, vibration frequency ω_e is 178.52cm^{-1}. Its force constants f_2, f_3, and f_4 are 0.9200aJ·nm^{-2}, --3.5700aJ·nm^{-3}, 11.2748aJ·nm^{-4} respectively. The other spectroscopic data for the ground state of Tc_2 molecule ω_eχ_e, B_e, α_e are 0.5523cm^{-1}, 0.0426cm^{-1}, 1.6331×10^{-4}cm^{-1} respectively.     

BCl和BCl2(2A1)的结构与势能函数

采用多种方法,配有多种基组对BCl和BCl2分子的基态结构进行优化计算,优选出B3P86/6-311++G(3df,3pd)方法对BCl分子进行计算得到基态为 、键长 =1.7159nm,谐振频率为 ;优选出QCISD/6-31G(d,p)方法对BCl2分子进行计算得到基态为 ,平衡核间距RBCl=0.17284nm、键角 =125.3466o、离解能 =8.0592eV,并计算出了谐振频率和力常数．在此基础上,运用多体展式理论方法,推导出BCl2分子的解析势能函数,其等值势能面图准确呈现出BCl2分子的结构特征及能量变化曲线．由此讨论了Cl+BCl和B+ClCl分子反应的势能面特征．可用于研究该分子的微观反应动力学特性．     

TiO基态 (X 3 Δr) 的势能函数与光谱常数

应用群论及原子分子反应静力学方法推导了TiO分子基态(X³Δ_r)的离解极限.采用不同的计算方法,包括密度泛函B3LYP,B3P86,BP86,B3PW91和MP2,MP4方法,结合不同基组计算了TiO分子基态的平衡核间距、能量和振动频率.研究表明,使用B3LYP方法,对O原子使用6-311+G基组,Ti原子使用6-311+ +G^**基组时计算得到的平衡几何结构、分子离解能和谐振频率与实验值符合得最好.使用优选出的方法和基组对T 关键词： TiO 势能函数 光谱常数 密度泛函理论     

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.