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1.
boldmath B3Σu-–X3Σg- transition in selenium dimer: ab initio multireference configuration interaction calculations 下载免费PDF全文
Theoretical investigation of low-lying electronic states and B3Σu-–X3Σg- transition properties of selenium dimer using size-extensivity singly and doubly excitation multireference configuration interaction theory with nonrelativistic all-electron basis set and relativistic effective core potential plus its split valence basis set is presented in this paper. The spectroscopic constants of ten low-lying Λ-S bound states have been obtained and compared with experiments. Spin-orbit calculations for coupling between B3Σu- sates and repulsive 1Πu, 5Πu states have been made to interpret the predissociation mechanisms of the B3Σu- state. The lifetimes of B3Σu- (v=0~6) have been calculated with scalar relativistic effects included or excluded, respectively, and reasonably agree with experimental values. 相似文献
2.
A combined cavity ringdown (CRD) and laser induced fluorescence (LIF) spectroscopic study on the A1∑+-X1∑+ transition of CuH has been presented.The CuH molecule,as well as its deuterated isotopologue CuD,are produced in a supersonic jet expansion by discharging H2(or D2) and Ar gas mixtures using two copper needles.Different profiles of relative line intensities are observed between the measured LIF and CRD spectra,providing an experimental evidence for the predissociation behavior in the A1∑+ state of CuH.The lifetimes of individual upper rotational levels are measured by LIF,in which the J''-dependent predissociation rates are obtained.Based on the previous theoretical calculations,a predissociation mechanism is concluded due to the strong spin-orbit coupling between the A1∑+ state and the lowest-lying triplet 3∑+ state,and a tunneling effect may also be involved in the predissociation.Similar experiments are also performed for CuD,showing that the A1∑+ state of CuD does not undergo a predissociation process. 相似文献
3.
OPTICAL-OPTICAL DOUBLE-RESONANCE EXCITATION SPECTRA OF THE (6d)1Πg, (7d)1Πg HIGH-LYING RYDBERG STATES IN Na2 下载免费PDF全文
Two 1Πg states of Na2 for v≤13 have been observed by using optical-optical double resonance (OODR) fluorescence excitation spectroscopy. The intermediate levels in B1Πu state are identified by the numerical calculations with the molec-ular constants for B1Πu←X1Σg+ transitions and confirmed by the complemen-tary A1Σg+←X1Σg+ polarization spectra. Absolute vibrational numberings of the (6d)1Πg and (7d)1Πg states are determined by comparing the experimental OODR excitation intensities with the simulated Franck-Condon factors. The Dnnham coef-ficients and the Rydberg-Klein-Rees (RKR) potential energy curves of the (6d)1Πg, (7d)1Πg states are reported. 相似文献
4.
The potential energy
function for ground state X5Σ- of the PuO molecule was worked out
by the quadratic configuration interaction of single and double substitution method, based
on the approximation of relativistic effective core potential for Pu atom and all-electron
6-311G basis set for O atom. The calculated results for Re,De,Be,αe,ωe
and ωeχe are 0.183nm,7.3909eV,0.3365,0.001642,781.15,and 2.77cm-1,respectively.In
addition,the thermodynamic functions ΔH0,ΔS0,ΔG0 and
Cp of the PuO(g) in standard state are also calculated,which are -118.88kJ/mol,96.16J/mol.K,-147.55kJ/mol,and
31.5656J/mol.K,respectively. All these results are in good agreement
with the experimental data. 相似文献
5.
Perturbation study via rotational-resolved spectrum in the triplet band d3Δ-a3∏(2, 1) of CO 下载免费PDF全文
The triplet band d3Δ-a3∏ (2, 1) of the CO molecule in the near infrared region of 12350--12850cm-1 has been observed and analysed by taking into account the perturbation interaction between the d3Δ(v = 2) and a3∏ (v = 9) states. The most perturbed lines and most precise perturbation parameters, \alpha2 and \beta2, and electronic perturbation constants,\xi _\e and \eta _\e , for the d3Δ (v= 2) and 3∏ (v = 9) states have been obtained. 相似文献
6.
Stability of the positively charged manganese centre in GaAs heterostructures examined theoretically by the effective mass approximation calculation near the Γ critical point 下载免费PDF全文
This paper describes an n-i-p-i-n model heterostructure with a manganese (Mn)-doped p-type base region to check the stability of a positively charged manganese AMn+ centre with two holes weakly bound by a negatively charged 3d5(Mn) core of a local spin S=5/2 in the framework of the effective mass approximation near the Γ critical point (k~0). By including the carrier screening effect, the ground state energy and the binding energy of the second hole in the positively charged centre AMn+ are calculated within a hole concentration range from 1 × 1016 cm-3 to 1 × 1017 cm-3, which is achievable by biasing the structure under photo-excitation. For comparison, the ground-state energy of a single hole in the neutral AMn0 centre is calculated in the same concentration range. It turns out that the binding energy of the second hole in the AMn+ centre varies from 9.27 meV to 4.57 meV. We propose that the presence of the AMn+ centre can be examined by measuring the photoluminescence from recombination of electrons in the conduction band with the bound holes in the AMn+ centre since a high frequency dielectric constant of varepsilon ∞ =10.66 can be safely adopted in this case. The novel feature of the ability to tune the impurity level of the AMn+ centre makes it attractive for optically and electrically manipulating local magnetic spins in semiconductors. 相似文献
7.
Influence of rotational excitation and collision energy on the stereo dynamics of the reaction: N(4S)+H2 (v = 0, j = 0, 2, 5, 10) →NH(X3∑-)+H 下载免费PDF全文
The N+H2 reaction has attracted a great deal of attention from both the experimental and the theoretical community, and most of the attention has been paid to the first excited state N(2D) atoms in collisions with hydrogen molecules and the scalar properties of the reaction. In this paper, we study the stereo dynamical properties and calculate the reaction cross sections of the N(4S) + H2 (v=0, j=0, 2, 5, 10) → NH(X3Σ-) + H using the quasi-classical trajectory (QCT) method on an accurate NH2 potential energy surface (PES) reported by Poveda and Varandas [Poveda L A and Varandas A J C 2005 Phys. Chem. Chem. Phys. 7 2867], in a collision energy range of 25 kcal·mol-1-140 kcal·mol-1. Results indicate that the reactant rotational excitation and initial collision energy both have a considerable influence on the distributions of the k-j′ correlation, the k-k′-j′ correlation and k-k′ correlation. The differential cross section is found to be sensitive to collision energy. 相似文献
8.
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10.
Investigations of spectroscopic parameters and molecular constants for X1Σg+, w3Δu, and W1Δu electronic states of P2 molecule 下载免费PDF全文
The potential energy curves (PECs) of three low-lying electronic states (X1Σg+, w3Δu, and W1Δu)of P2 molecule are investigated using the full valence complete active space self-consistent field (CASSCF) method followed by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in conjunction with the correlation-consistent basis set in the valence range. The PECs of the electronic states involved are modified by the Davidson correction and extrapolated to the complete basis set (CBS) limit. With these PECs, the spectroscopic parameters of the three electronic states are determined and compared in detail with the experimental data. The comparison shows that excellent agreement exists between the present results and the available experimental data. The complete vibrational states are computed for the w3Δu, and W1Δu electronic states when the rotational quantum number J equals zero and the vibrational level G(v), the inertial rotation constant Bv, and the centrifugal distortion constant Dv of the first 30 vibrational states are reported, which accord well with the experimental data. The present results show that the two-point extrapolation scheme can obviously improve the quality of spectroscopic parameters and molecular constants. 相似文献
11.
The multiphoton ionization spectra of dimethylamine are given in the 445-470 nm region. A time of flight mass spectrometer was used,and experiment was done under collision free condition. It is found that (2+2) resonance enhanced multiphoton ionization through (nN,3s) Rydberg state produces parent ions which endure pseudo-α and C—N bond cleavages. The former forms CH3N+H=CH2 ions,and the latter gives CH2=N+H2 ions . 相似文献
12.
基于北京谱仪收集的4.03GeV质心系能量下e+e-对撞数据,分析τ±τ±→e±+π±+nπ0+ν's(n=0,1,2)事例,给出分支比值Br(τ±→π±ντ)=(11.64±0.49+0.76-0.73%,Br(τ±→π±π0ντ)=(24.00±1.34+1.36-1.30%,Br(τ±→π±2π0ντ)=(9.39±1.68+1.69-1.66%. 相似文献
13.
Theoretical study of structure and analytic potential energy function for the ground state of PO2 molecule 下载免费PDF全文
In this paper, the energy, the equilibrium geometry, and the harmonic frequency of the ground electronic state of PO2 are computed using B3LYP, B3P86, CCSD(T), and QCISD(T) methods in conjunction with 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 PO2 molecule. It is shown that the ground state of the PO2 molecule has C2v symmetry and its ground electronic state is X2A1. The equilibrium parameters of the structure are RP-O=0.1465 nm, d=19.218 eV. The bent vibrational frequency ν1=386 cm-1, the symmetric stretching frequency ν2=1095 cm-1, and the asymmetric stretching frequency ν3=1333 cm-1 are obtained. On the basis of atomic and molecular reaction statics, the reasonable dissociation limit for the ground state of the PO2 molecule is determined. Then the analytic potential energy function of the PO2 molecule is first derived by using the many-body expansion theory. The potential curves correctly reproduce the configurations and the dissociation energy for the PO2 molecule. 相似文献
14.
STUDY OF ANALYTIC POTENTIAL ENERGY FUNCTION AND STABILITY FOR PuOn+ WITH DENSITY FUNCTIONAL THEORY 下载免费PDF全文
The theoretical study of PuOn+(n=1,2,3) using a density functional method shows that PuO+ (X6Σ-) and PuO2+ (X5Σ-, 7Σ-, 9Σ-) ions are stable, and the PuO3+ (4Σ+, 6Σ+) ion is unstable. The analytic potential energy functions of X6Σ- for PuO+ and X5Σ-, 7Σ-, 9Σ- for PuO2+ have been derived, and their force constants and spectroscopic data have been calculated. 相似文献
15.
In this paper, we have calculated the elastic scattering of high energy electrons with nuclei C12 by phase shift calculation.We take the charge distribution of the nucleus C12 as following:(1) exponential distribution:ρ(x)=ρ0θ-x/a, (2) gaussian distribution:ρ(x)=ρ0e(-x2/a2),(3) uniform distribution: ρ(x) ={ρ0 when 0kR, where a and b are the parameters, and the constant R is the radius of the nucleus C12. The energy of the electrons is 187 Mev.The result of the calculation shows that the gaussian distribution confirms the experimental result better than the other two kinds of distributions, and gives R=(12)1/3r0, where r0=1.35×10-13 cm. 相似文献
16.
PHOTO-INDUCED ENHANCEMENT OF THE THIRD-ORDER OPTICAL NONLINEARITY IN AZOBENZENE COMPOUND ON THE PICOSECOND TIME SCALE 下载免费PDF全文
Photo-induced enhancement processes of the third-order optical nonlinearity were observed in azobenzene solution under a 3Ops pulse pumping at 532 nm. Weinvestigated the time evolotion of the enhancement and found that it was mainly due to thc population of the first excited stale. By theoretical simulation of the enhancement processes, the values of the hyperpolarizabilities of the sample-molecules at ground state and at excited state, γg and γs1 were determined to be 1.11×10-33 esu and 7.40×10-33, respectively. 相似文献
17.
Spectroscopic investigations on NO+(x1∑+,a3∑+,A1Ⅱ) ion using multi-reference configuration interaction method and correlation-consistent sextuple b 下载免费PDF全文
Three low-lying electronic states (x1∑+,a3∑+,and A1Ⅱ) of NO+ ion are studied using the complete active space self-consistent-field (CASSCF) method followed by highly accurate valence internally contracted multi-reference configuration interaction (MRCI) approach in combination of the correlation-consistent sextuple basis set augmented with diffuse functions, aug-cc-pV6Z. The potential energy curves (PECs) of the NO+(x1∑+,a3∑+,A1Ⅱ) are calculated. Based on the PECs, the spectroscopic parameters Re, De, ωe, ωeχe, α e, Be, and D0 are reproduced, which are in excellent agreement with the available measurements. By numerically solving the radial Schrödinger equation of nuclear motion using the Numerov method, the first 20 vibrational levels, inertial rotation and centrifugal distortion constants of NO+(x1∑+,a3∑+,A1Ⅱ) ion are derived when the rotational quantum number J is equal to zero (J = 0) for the first time, which accord well with the available measurements. Finally, the analytical potential energy functions of these states are fitted, which are used to accurately derive the first 20 classical turning points when J = 0. These results are compared in detail with those of previous investigations reported in the literature. 相似文献
18.
MgF自由基被认为是适用于直接激光冷却的候选分子之一. 本文利用激光诱导荧光技术研究了MgF A2π-X2Σ+电子跃迁系统的转动分辨光谱. 在超声射流膨胀条件下利用两个镁针对SF6/Ar气体混合放电产生MgF自由基. 在348∽370 nm范围内,实验记录了属于Δv=0,±1三个序的19个振动带. 通过对实验光谱的转动分析,确定了X2Σ+和A2π态的精确光谱常数. 利用实验结果结合和Rydberg-klein-rees方法计算了包括Franck-Condon因子(FCFs)在内的光谱常数. 实验结果和理论计算的FCFs之间存在显著差异,表明FCFs几乎不依赖于A2π态自旋-轨道耦合效应. 本文确定的势能曲线和FCFs为MgF分子激光冷却方案的理论模拟提供了必要的光谱数据. 相似文献
19.
The P-branch emission spectra of (4,1) and (3,1) bands of the A1Π-X1Σ+ system of IrN molecule are studied using an analytical formula which is derived from elementary expression of molecular total energy by taking multiple spectral differences. It not only reproduces the known experimental transition lines, but also predicts the unknown spectral lines up to J= 80 for each band by using a group of fifteen known experimental transition lines. 相似文献
20.
Ab initio calculation of accurate dissociation energy, potential energy curve and dipole moment function for the A1∑ + state 7LiH molecule 下载免费PDF全文
The reasonable dissociation limit of the A1∑+ state
$^{7}$LiH molecule is obtained. The accurate dissociation energy and the
equilibrium geometry of this state are calculated using a
symmetry-adapted-cluster configuration-interaction method in complete active space
for the first time. The whole potential energy curve and the dipole moment
function for theA1∑+ state are calculated over a wide
internuclear separation range from about 0.1 to 1.4\,nm. The calculated
equilibrium geometry and dissociation energy of this potential energy curve
are of R_{\e}=0.2487\,nm and D_{\e}=1.064\,eV, respectively. The unusual negative
values of the anharmonicity constant and the vibration-rotational coupling
constant are of \textit{\omega }_{\e}\textit{\chi
}_{\e}=--4.7158cm^{ - 1} and \textit{\alpha
}_{\e}=--0.08649cm^{ -1}, respectively. The vertical excitation
energy from the ground to the
A1∑+ state is calculated and the value is of 3.613\,eV at
0.15875nm (the equilibrium position of the ground state). The highly
anomalous shape of this potential energy curve, which is exceptionally flat
over a wide radial range around the equilibrium position, is discussed in
detail. The harmonic frequency value of 502.47cm1 about this state
is approximately estimated. Careful comparison of the theoretical
determinations with those obtained by previous theories about the
A1∑+ state dissociation energy clearly shows that the present
calculations are much closer to the experiments than previous theories, thus
represents an improvement. 相似文献