Zhu Zheng-He

Study of analytic potential energy function and stability for PuOn + with density functional theory

The theoretical study of PuOn + (n=1,2,3) using a density functional method shows that PuO+ (X6Si-) and PuO2+ (X5Si-, 7Si-, 9Si-) ions are stable and the PuO3+ (4Si+, 6Si+) ion is unstable. The analytic potential energy functions of X6Si- for PuO+ and X5Si-, 7Si-, 9Si- for PuO2+ have been derived and their force constants and spectroscopic data have been calculated.

Geometry and electronic properties of Cun (n≤9)

The equilibrium geometries and the atomization energies of Cun(n≤9) clusters have been calculated using the B3LYP/LANL2DZ method. It is shown that the clusters do not copy the bulk structures and undergo significant geometrical changes with size and the atomization energy per atom increases monotonically with size. By analysing the energy level distribution, the Fermi level, HOMO–LUMO gaps, the electron affinities and the ionization potentials are calculated and the results are in reasonable agreement with experiment. These electronic properties are found to be strongly structure dependent, which can be used to determine which of the low-lying structures is observed experimentally.

Geometrical structures, vibrational frequencies, force constants and dissociation energies of isotopic water molecules （H2O, HDO, D2O, HTO, DTO, and T2O） under dipole electric field

The dissociation limits of isotopic water molecules are derived for the ground state. The equilibrium geometries, the vibrational frequencies, the force constants and the dissociation energies for the ground states of all isotopic water molecules under the dipole electric fields from ?0.05 a.u. to 0.05 a.u. are calculated using B3P86/6-311++G(3df,3pf). The results show that when the dipole electric fields change from ?0.05 a.u. to 0.05 a.u., the bond length of H?O increases whereas the bond angle of H?O?H decreases because of the charge transfer induced by the applied dipole electric field. The vibrational frequencies and the force constants of isotopic water molecules change under the influence of the strong external torque. The dissociation energies increase when the dipole electric fields change from ?0.05 a.u. to 0.05 a.u. and the increased dissociation energies are in the order of H2O, HDO, HTO, D2O, DTO, and T2O under the same external electric fields.

Potential energy surfaces of ozone in the ground state

Equilibrium parameters of ozone, such as equilibrium geometry structure parameters, force constants and dissociation energy are presented by CBS-Q ab initio calculations. The calculated equilibrium geometry structure parameters and energy are in agreement with the corresponding experimental values. The potential energy function of ozone with a C2v symmetry in the ground state is described by the simplified Sorbie–Murrell many-body expansion potential function according to the ozone molecule symmetry. The contour of bond stretching vibration potential of an O3 in the ground state, with a bond angle (�) fixed, and the contour of O3 potential for O rotating around O1–O (R1), with O1–O bond length taken as the one at equilibrium, are plotted. Moreover, the potentials are analysed.

Potentional Energy Function and Stability of PuO n

用密度泛函Ｂ３ＬＹＰ方法对ＰｕＯ＾ｎ＋（ｎ＝１，２，３）分子离子进行了理论研究。结果表明，ＰｕＯ＾＋、ＰｕＯ＾２＋分子离子能稳定存在，电子状态是Ｘ＾６∑＾－（ＰｕＯ＾＋）、Ｘ＾５（ＰｕＯ＾２＋）、＾９∑＾－（ＰｕＯ＾２＋、＾７∑＾－（ＰｕＯ＾２＋），导出了相应的几何性质，力学性质和光谱数据。ＰｕＯ＾３＋分子离子不能稳定存在。

Density functional theory study of MgnNi2 (n = 1–6) clusters

The geometries of MgnNi2(n = 1–6) clusters are studied by using the hybrid density functional theory (B3LYP) with LANL2DZ basis sets. For the ground-state structures of MgnNi2 clusters, the stabilities and the electronic properties are investigated. The results show that the groundstate structures and symmetries of Mg clusters change greatly due to the Ni atoms. The average binding energies have a growing tendency while the energy gaps have a declining tendency. In addition, the ionization energies exhibit an odd—even oscillation feature. We also conclude that n = 3, 5 are the magic numbers of the MgnNi2 clusters. The Mg3Ni2 and Mg5Ni2 clusters are more stable than neighbouring clusters, and the Mg4Ni2 cluster exhibits a higher chemical activity.Possible geometrical structures and relative stabilities of ［Mg(NH 2 ) 2 ］ n ( n =1—5) clusters are studied by using the hybrid density functional theory (B3LYP) with 6-31G * basis sets. For the most stable isomers, the electronic structure, vibrational properties, bond properties and ionization potentials are analyzed. The calculated results show the following tendencies: the Mg and N atom are bonded with each other to form catenulate structures. The bond lengths for ［Mg(NH 2 ) 2 ］ n ( n =1—5) clusters are about 0.190—0.234nm for Mg—N, and 0.101—0.103 nm for the N—H bonds, the bond angles of H—N—H are about 100.2°—107.5°. The population analysis suggests that the natural charge of N atoms are about -1.551 e —-1.651 e , that of Mg atoms are about 1.585 e —1.615 e , that of H atoms are about 0.369 e —0.403 e , and that of—NH 2 are about -0.784 e —-0.845 e , and the bonds between Mg and —NH 2 have strong ionicity. The comparative study of structures and spectra of clusters and crystal show that —NH 2 keeps the integrity in the crystal and in clusters.

Density functional theory study on Ni-doped MgnNi (n = 1–7) clusters

The possible geometrical and the electronic structures of small MgnNi (n = 1?7) clusters are optimised by the density functional theory with a LANL2DZ basis set. The binding energy, the energy gap, the electron affinity, the dissociation energy and the second difference in energy are calculated and discussed. The properties of MgnNi clusters are also discussed when the number of Mg atom increases.

Spin polarization effect for Tc2 molecule

Density functional method (DFT) (B3p86) of Gaussian98 has been used to optimize the structure of the Tc2 molecule. The result shows that the ground state for Tc2 molecule is an 11-multiple state and its electronic configurationis 11∑^-g, which shows the spin polarization effect of Tc2 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 Tc2 molecule is an 11-multiple state is indicative of the spin polarization effect of Tc2 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 thatthe energy of Tc2 molecule is minimized. It can be concluded that the effect of parallel spin of the Tc2 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 11Eg and other states of Tc2 molecule are derived. Dissociation energy De for the ground state of T~2 molecule is 2.266eV, equilibrium bond length Re is 0.2841nm, vibration frequency We is 178.52cm^-1. Its force constants f2, f3, and f4 are 0.9200aJ.nm^-2,-3.5700aJ·nm^-3, 11.2748aJ.nm^-4 respectively. The other spectroscopic data for the ground state of Tc2 molecule WeXe,Be, ae are 0.5523cm^-1, 0.0426cm^-1, 1.6331×10^-4cm^-1 respectively.Density functional method (DFT) (B3p86) of Gaussian98 has been used to optimize the structure of the Tc2 molecule. The result shows that the ground state for Tc2 molecule is an 11-multiple state and its electronic configuration is 11Σg−, which shows the spin polarization effect of Tc2 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 Tc2 molecule is an 11-multiple state is indicative of the spin polarization effect of Tc2 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 Tc2 molecule is minimized. It can be concluded that the effect of parallel spin of the Tc2 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 11Σg− and other states of Tc2 molecule are derived. Dissociation energy De for the ground state of Tc2 molecule is 2.266eV, equilibrium bond length Re is 0.2841nm, vibration frequency ωe is 178.52cm−1. Its force constants f2, f3 and f4 are 0.9200aJ.nm−2, –3.5700aJ.nm−3, 11.2748aJ.nm−4 respectively. The other spectroscopic data for the ground state of Tc2 molecule ωeχe, Be,αe are 0.5523cm−1, 0.0426cm−1, 1.6331× 10−4cm−1 respectively.

Spin polarization effect of Ni2 molecule

The density functional theory (DFT) method (b3p86) of Gaussian 03 is used to optimize the structure of the Ni2 molecule. The result shows that the ground state for the Ni2 molecule is a 5-multiple state, symbolizing a spin polarization effect existing in the Ni2 molecule, a transition metal molecule, but no spin pollution is found because the wavefunction of the ground state does not mingle with wavefunctions of higher-energy states. So the ground state for Ni2 molecule, which is a 5-multiple state, is indicative of spin polarization effect of the Ni2 molecule, that is, there exist 4 parallel spin electrons in Ni2 molecule. The number of non-conjugated electrons is greatest. These electrons occupy different spatial orbitals so that the energy of the Ni2 molecule is minimized. It can be concluded that the effect of parallel spin in the Ni2 molecule is larger than that 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 of the ground state and other states of the Ni2 molecule are derived. The dissociation energy De for the ground state of the Ni2 moleculeis 1.835 eV, equilibrium bond length Re is 0.2243 nm, vibration frequency ωe is 262.35 cm-1. Its force constants f2,f3 and f4 are 1.1901 aJ.nm-2, -5.8723 aJ.nm-3, and 21.2505 aJ.nm-4 respectively. The other spectroscopic data for the ground state of the Ni2 molecule ωeχe, Be andre are 1.6315 cm-1, 0.1141 cm-1, and 8.0145×10-4cm-1 respectively.

Spectrum Simulation of Li-Like Aluminium Plasma

X-ray emission spectra for L-shell of Li-like aluminium ions are simulated by using the flexible atomic code based on the collisional radiative model. Atomic processes including radiative recombination, dielectronic recombination, collisional ionization and resonance excitation from the neighbouring ion (Al9+ and Al11+) charge states of the target ion (Al10+) are considered in the model. In addition, the contributions of different atomic processes to the x-ray spectrum are analysed. The results show that dielectronic recombination, radiative recombination, collisional ionization and resonance excitation, other than direct collisional excitation, are very important processes.