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1.
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   

2.
张金平  程新路  张红  杨向东 《中国物理 B》2011,20(6):60401-060401
Three low-lying electronic states (x1+,a3+,and A1) 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+,A1) 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+,A1) 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   

3.
金星南 《物理学报》1959,15(1):25-31
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   

4.
杨国  张国营  高娇  薛刘萍  夏天  张学龙 《中国物理 B》2011,20(1):17802-017802
The superexchange interaction on a magnetic ion may be represented by an effective field Hm = λM in some paramagnetic materials, here λ is the coefficient of effective field and M = χHe with χ being the magnetic susceptibility and He being the applied field. The variation of the equivalent λχ with the dynamic applied field is given and the crystal field-splitting levels of the excited configuration 4f75d1 of the Tb3+ ion are calculated in the Tb3Ga5O12. By means of the effective field Hm and the applied field He, the Faraday rotation of Tb3Ga5O12 at 6 K and 41 K, under the high magnetic field and at 0.63 μm wavelength, are presented. Our calculated results are in agreement with the experimental data.  相似文献   

5.
Yb3+/Dy3+ co-doped Al2O3 nanopowders have been prepared by the non-aqueous sol-gel method and their up- conversion photoluminescence spectra are measured under excitation by 980-nm semiconductor laser. The results show that there are comparatively abundant spectra of up-conversion emissions centered at 378, 408, 527 and 543, and 663 nm, corresponding to 4G9/26H13/2, 4G9/26H11/2, 4I15/26H13/2, and 4F9/26H11/2 transitions of Dy3+, respectively. Two-photon and three-photon processes are involved in ultraviolet, violet, green, and red up-conversion emissions. The energy transition between Yb3+ and Dy3+ is discussed.  相似文献   

6.
We study long-time limit behavior of the solution of atom's master equation, for the first time we derive that the probability of the atom being in the α-th (α =j+1-jz, j is the angular momentum quantum number, jz is the z-component of angular momentum) state is {(1-K/G)/[1-(K/G)2j+1]}(K/G)α-1 as t→+∞, which coincides with the fact that when K/G > 1, the larger the α is, the larger probability of the atom being in the α-th state (the lower excited state). We also consider the case for some possible generalizations of the atomic master equation.  相似文献   

7.
Zeng Hui  Zhao Jun 《中国物理 B》2012,21(7):78202-078202
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   

8.
宫明艳  许小涛  凤尔银 《中国物理 B》2011,20(11):113401-113401
Collisions of cold and ultracold BH in the v=0 level with the He atom are investigated using the quantum mechanical scattering formulation. The elastic and the inelastic cross sections are calculated using the two-dimensional ab initio potential energy surface. It is shown that the elastic cross section is larger than the inelastic one. When the collision energy is very low, the elastic cross section follows the Wigner threshold law and is one order of magnitude larger than that of He-O2, while it is much smaller than that of He-H2. The efficiency of the rotationally quenching state is given. The Δj=-1 transition is most efficient. The resonances are also found to occur at about the same translational energy (0.1-1 cm-1), which gives rise to steps in the rate coefficient at temperatures around 0.1-1 K.  相似文献   

9.
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   

10.
The photodissociation dynamics of isocyanic acid (HNCO) has been studied by the timesliced velocity map ion imaging technique at 193 nm. The NH(a1Δ) products were measured via (2+1) resonance enhanced multiphoton ionization. Images have been accumulated for the NH(a1Δ) rotational states in the ground and vibrational excited state (v=0 and 1). The center-of-mass translational energy distribution derived from the NH(a1Δ) images implies that the CO vibrational distributions are inverted for most of the measured 1NH(v|j) internal states. The anisotropic product angular distribution observed indicates a rapid dissociation process for the N-C bond cleavage. A bimodal rotational state distribution of CO(v) has been observed, this result implies that isocyanic acid dissociates in the S1 state in two different pathways.  相似文献   

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