共查询到19条相似文献,搜索用时 140 毫秒
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采用密度泛函理论的B3LYP方法和二次组态相互作用(QCISD(T))方法优化计算了OH分子基态(X2Π)的平衡结构、振动频率和离解能.根据原子分子反应静力学原理,导出了OH分子基态(X2Π)的合理离解极限,采用最小二乘法拟合Murrell-Sorbie函数得到了相应的势能函数和与该基态相对应的光谱常数(Be,αe,ωe和ωeχe),计算结果与实验数据符合得相当好.
关键词:
OH分子
2Π)')" href="#">基态(X2Π)
势能函数 相似文献
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用相对论有效原子实势(RECP)和密度泛函(B3LYP/SDD)方法研究了UH,UH2基态和低激发态的结构和势能函数,导出了分子的光谱数据.结果表明,UH和UH2的基电子状态分别为X4Π和X3A2,离解能分别为2.886eV和5.249eV,UH2具有C2v对称性,得到了UH和UH2的几个不同的低激发态的结构与光谱数据.应用多体项展式理论以及数字拟合方法
关键词:
UH
2')" href="#">UH2
势能函数
分子结构 相似文献
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使用密耦近似(Close-Coupling)方法、采用Tang-Toennies势模型计算了惰性气体原子Ne与H2分子及同位素D2分子在碰撞能量为83.8 meV时的微分散射截面及分波截面, 并与实验值和文献值进行比较.计算得到的微分散射截面值与实验值符合得较好,分波截面值与文献值也相符合.使用同样的方法和模型,文中对Ne-H2(D2,T2)三个体系的微分截面和分波截面进行了系统计算和比较分析,得出对称同位素替代碰撞体系的散射截面规律.
关键词:
2(D2')" href="#">Ne-H2(D2
2)碰撞')" href="#">T2)碰撞
Tang-Toennies势模型
密耦方法
同位素替代 相似文献
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采用密度泛函理论(DFT)的B3P86方法和相对论有效原子实势理论模型(RECP),对BH2,BH2+和BH2-分子进行了优化,得到这些分子基态的电子状态分别是2A′,3A′,3A″. 计算也得到了BH2的分子结构和势能函数,它的离解能是7.752eV,BH2分子具有C2V关键词:
2')" href="#">BH2
分子结构
势能函数 相似文献
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采用Gaussian 98程序,运用B3LYP方法,对Pd和Pb原子采用收缩价基组LANL2DZ,对Pb2和PdPb2分子的微观结构进行了理论计算. 由于Pb2分子离解后一个Pb原子处于基态,另一个Pb原子处于激发态,采用最小二乘法拟合Pb2分子的势能函数,选用的函数形式为Murrell-Sorbie势能函数加上开关函数. 使用多体展式理论导出了势函数中的参数进而给出PdPb2分子基态势函数的解析表达式,其势能面准确地复现了PdPb2分子的两个稳定构型(C2V和C∞v)及其能量关系.
关键词:
2')" href="#">Pb2
2')" href="#">PdPb2
势能函数 相似文献
11.
运用二次组态相关(QCISD)方法,分别选用6-311++G(3df,3pd)和D95(3df,3pd)基组,对BH2和AlH2分子的结构进行了优化计算,得到BH2分子的稳态结构为C2v构型,电子态为2A1、平衡核间距RBH=0.1187nm、键角∠HBH=128.791°、离解能De=3.65eV、基态振动频率ν1(a1)=1020.103cm-1,ν2(a1)=2598.144cm-1,ν3(b2)=2759.304cm-1.AlH2分子的稳态结构也为C2v构型,电子态为2A1、平衡核间距RAlH=0.1592nm、键角∠HAlH=118.095°、离解能De=2.27eV、基态振动频率ν1(a1)=780.81cm-1,ν2(a1)=1880.81cm-1,ν3(b2)=1910.46cm-1.采用多体项展式理论推导了基态BH2和AlH2分子的解析势能函数,其等值势能图准确再现了BH2和AlH2分子的结构特征及其势阱深度与位置.分析讨论势能面的静态特征时得到BH+H→BH2反应中存在鞍点,活化能为150.204kJ/mol;AlH+H→AlH2反应中也存在鞍点,活化能为54.8064kJ/mol.
关键词:
2')" href="#">BH2
2')" href="#">AlH2
Murrell-Sorbie函数
多体项展式理论
解析势能函数 相似文献
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The equilibrium structures and the electronic, spectroscopic and thermodynamic properties of small Pun (n=2-5) molecules are systematically investigated using the methods of general gradient approximation (GGA) of density functional theory (DFT). The results show that the bond length of the lowest-energy structure of Pu2 is 2.578 AA. The ground state structure of Pu3 is a triangle with D3h symmetry, whereas for Pu4, the ground state structure is a square (D4h) and the spin polarization of 16 for molecule Pu5 with square geometry (D4h) is the most stable structure. For the ground state structures, the vibrational spectra as well as thermodynamic parameters are worked out. In addition, the values for the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) along with the energy gap of all the Pu2-5 structures are presented. The relevant structural and chemical stabilities are predicted. 相似文献
13.
Abstract Three new bands of the B 2Σ+–X 2Σ+ system of 12C17O+ have been investigated using conventional spectroscopic techniques. The spectra were observed in a graphite hollow‐cathode lamp by discharging molecular oxygen (enriched in about 45% of the 17O2 isotope) under 1.0 Torr pressure. The rotational analysis of the 2–4, 2–5, and 2–6 bands was performed with the effective Hamiltonian of Brown (Brown et al., J. Mol. Spectrosc. 1979; 74: 294–318). Molecular constants were derived from a merge calculation, including both the current wavenumbers and the spectroscopic data published by the authors previously. The principal equilibrium constants for the ground state of 12C17O+ are ωe=2185.9658(84), ωe x e = 14.7674(11), B e=1.927001(38), αe=1.8236(22)×10?2, γe=?0.331(28)×10?4, D e=6.041(12)×10?6, βe=0.100(31)×10?7 cm?1, and the equilibrium constants for the excited state are σe=45876.499(15), ωe=1712.201(12), ωe x e=27.3528(39), B e=1.754109(35), αe=2.8706(57)×10?2, γe = ?1.15(19)×10?4, D e=7.491(20)×10?6, βe=2.13(12)×10?7, γe = 2.0953(97)×10?2, and αγe=?9.46(59)×10?4 cm?1, respectively. Rydberg–Klein–Rees potential energy curves were constructed for the B 2Σ+ and X 2Σ+ states of this molecule, and Franck–Condon factors were calculated for the vibrational bands of the B–X system. 相似文献
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The spectrum of the ν7 band of cis-ethylene-d2 (cis-C2H2D2) has been recorded with an unapodized resolution of 0.0063 cm−1 in the 740-950 cm−1 region using a Bruker IFS 125 HR Fourier transform infrared spectrometer. By fitting 2186 infrared transitions of ν7 with a standard deviation of 0.00060 cm−1 using a Watson’s A-reduced Hamiltonian in the Ir representation, accurate rovibrational constants for ν7 = 1 state have been derived. The band center of ν7 has been found to be 842.20957 ± 0.00004 cm−1. In a simultaneous fit of 1331 infrared ground state combination differences from the present ν7 transitions, together with 22 microwave frequencies, ground state constants have been improved. The rms deviation of the ground state fit was 0.00027 cm−1. 相似文献
16.
E. CanèL. Fusina H. BürgerW. Jerzembeck S. BrünkenF. Lewen G. Winnewisser 《Journal of Molecular Spectroscopy》2002,215(1):1-9
Infrared spectra of PD3 have been measured in the 20-320 cm−1 range and in the region of the ν2/ν4 and ν1/ν3 fundamental bands near 750 and 1690 cm−1, respectively, with a resolution of ca. 0.0025 cm−1. Furthermore, submillimeter-wave spectra covering the J=4-3, 13-12, and 14-13 clusters in the vibrational ground state were recorded. The observed ΔJ=+1 rotational lines were augmented by about 5500 ground state combination differences formed from transitions belonging to the fundamental bands. Of these, 1300 involved perturbation-allowed lines with ΔK≠0. These data and observations taken from the literature were appropriately weighted and fitted to 14 ground state molecular constants. The A and B reductions of the rotational Hamiltonian were found to be equivalent. Improved effective ground state and equilibrium structures were determined for both PH3 and PD3; the equilibrium structures, re (PH)=141.1607(83) pm and αe (HPH)=93.4184(95)° and re (PD)=141.1785(57) pm and αe (DPD)=93.4252(68)°, are in good agreement. 相似文献
17.
Friedrich Grein 《Molecular physics》2020,118(18)
CCSD(T) and MP2 results using the aug-cc-pV5Z basis set are reported for chain, cyclic and other structures of the clusters (H2)n, n?=?2-8, (CO2)n, n?=?2-6 and (HF)n, n?=?2-8. In chain-like structures of (H2)n and (CO2)n, with the bonding type of the dimer maintained, the dissociation energy De of the dimer doubles for the trimer, triples for the tetramer, and so on. Due to these systems being dominated by short-range forces, interactions are essentially restricted to neighbouring monomers. For other types of (H2)n and (CO2)n structures, the multipliers relative to the dimerisation energy can be much higher. Dissociation energies for the hexamers in S6 symmetry of both H2 (379?cm?1) and CO2 (4925?cm?1) are over ten times the respective dimerisation energies. For the chain-like trimer of HF, however, De is in excess of double the dimer value. Mainly due to longer-range dipolar forces, the interactions reach beyond the neighbouring monomers. The interaction energy between HF monomers in chains follows an approximate R?2 (R being the F–F distance) relationship, The calculated dissociation energies of the HF octamer are 15,985?cm?1 (factor of 10.4) for the chain, and 21,003?cm?1 (factor of 13.7) for the C6h cyclic structure. 相似文献
18.
采用包含Davidson修正的多参考组态相互作用(MRCI+Q)方法结合6-311++G(3df,3pd)基组计算了LiC分子基态(X4Σ-)以及五个低电子激发态(a2Π,b2Δ,c2Σ-,d2Σ+,A4Π)的势能曲线.将得到的势能曲线拟合到Murrell-Sorbie解析势能函数形式,确定了对应态的平衡结构Re、谐振频率ωe和离解能De等光谱数据,计算值与仅有的几个其他结果进行了比较.通过求解核运动的薛定谔方程首次报道了LiC分子几个低电子态在J=0下的振动能级、转动惯量和六个离心畸变常数(Dν,Hν,Lν,Mν,Nν和Oν). 相似文献
19.
S.W. Arteaga Z.T. Martin J. Mayo E.A. McIlhattan J.-M.F. Moreau M.J. Pilkenton M.J. Polston B.T. Robertson E.N. Wolf 《Journal of Molecular Spectroscopy》2007,243(2):253-266
Pressure broadening and shift coefficients have been measured for the ν1 + ν3 band of acetylene, C2H2, broadened by N2, H2, D2, air, and the noble gases at 295 K. Coefficients are reported for lines between 6470 and 6612 cm−1 (1512-1546 nm). The pressure broadening coefficients are in general agreement with those reported for other vibrational bands, indicating that they are insensitive to vibrational excitation. The pressure shift coefficients, by contrast, are found to differ substantially among vibrational bands. 相似文献