利用电荷自洽离散变分Xα(SCC-D V-Xα)方法计算了钒基固溶体中钒氢反应前后钒及其氢化物(V H x,x=0,1,2)、假定原子簇模型V H 鄢x(x=1,2)和V H x'(x=0,1)的电子结构.结果表明:钒与氢气反应生成V H 时,化学效应和结构效应都使V 3d和...利用电荷自洽离散变分Xα(SCC-D V-Xα)方法计算了钒基固溶体中钒氢反应前后钒及其氢化物(V H x,x=0,1,2)、假定原子簇模型V H 鄢x(x=1,2)和V H x'(x=0,1)的电子结构.结果表明:钒与氢气反应生成V H 时,化学效应和结构效应都使V 3d和H 1s轨道向低能量方向移动,氢化物V H 中V 3d和H 1s轨道重叠最多,V -H 之间的相互作用较强。V H 再与氢气反应生成V H 2时,结构效应使V 3d和H 1s轨道都向高能量方向移动,氢化物V H 2中V 3d和H 1s轨道重叠最少,V 和H 之间的相互作用较弱。氢化物V H 和V H 2中不仅存在离子性相互作用,而且还存在共价性相互作用.结构效应导致V H 2中V -H 键的共价性减弱,从而导致V H 2中V 和H 之间的相互作用减弱。氢化物V H 的费米能级比V H 2的低,说明V H 更稳定.展开更多
The effect of equi weight electrostatic field on transesterification of MeCOOBu with EtOH in the presence of base catalyst in liquid phase was investigated. The conversion of forward reaction and backward reaction was...The effect of equi weight electrostatic field on transesterification of MeCOOBu with EtOH in the presence of base catalyst in liquid phase was investigated. The conversion of forward reaction and backward reaction was slightly enhanced in the equi weight field ( E =1×10 5 V/m). SCC DV X α calculations showed that the HOMO energy level of CH 2O was decreased by about 9 6 eV in H + field, while increased by about 23 7 eV in O 2- field. It is concluded that the activation energy of the reaction in equi weight electrostatic field is almost the same as in free field, owing to the same potential energy change of the reactants, transition states and products. In the unequi weight electrostatic field, the negative charge center seems to be the active site for reactants or products, while the positive one seems to be the active site for transition states, resulting in great decrease in the activation energy.展开更多
The geometries of imidazole and its derivatives were respectively optimized by using ab initio method, and the molecular orbital energy levels and the charge densities were obtained for their optimum geometries. The f...The geometries of imidazole and its derivatives were respectively optimized by using ab initio method, and the molecular orbital energy levels and the charge densities were obtained for their optimum geometries. The frontier orbital energy levels, and the net charges of N (1) atom and the imidazole ring of those molecules were obtained with ab initio and SCC-DV-Xα methods. It was found that the inhibition properties of those compounds change with the highest occupied molecular orbital energy levels, and the net charges of N (1) atom. We took four iron atoms on the crystal plane (100) of α-iron as the surface which was used to study the adsorption towards the inhibitors. The adsorption models of the inhibitor to be adsorbed on the Fe-cluster surface were optimized with SCC-DV-Xα method. It turns out that the most favorable model is that the inhibitor molecule is adsorbed on the Fe-cluster surface in an inclined state. The calculation shows that the stabilization energies of the systems are well correlated with the inhibition efficiencies.展开更多
SCC-DV-X method was used for the theoretical calculation of heteropoly an- ion , [SiMoO40]4- . and heteropoly blue anions,[SiMo2 Mo10O40]6 and [SiMo4 Mo!; O' 1,-. Th. f.o.ti.. .ol...l.. orbital. , orbital e.e.gi....SCC-DV-X method was used for the theoretical calculation of heteropoly an- ion , [SiMoO40]4- . and heteropoly blue anions,[SiMo2 Mo10O40]6 and [SiMo4 Mo!; O' 1,-. Th. f.o.ti.. .ol...l.. orbital. , orbital e.e.gi.. , Fe.mi 1...l. , the o.- cupied numbers of basis functions , free valences , Mulliken populations and the fig- ure of the total density of states have been obtained. The theoretical analysis indi- cates that all the atoms in the anions participate in chemical reactions , but Oc and Od have higher chemical activities than other atonts , which is supported by the ex- perimental results. The heteropoly hue anions with the α-Keggin structure distort a little and the levels of valence orbitals demonstrate that [SiMo4 Mo8O40]8 can form a six-electron heteropoly blue anoint by accepting two electrons.展开更多
The electronic structures of several dinuclears and trinuclears of molybdenum containing thiolates complexes have been calculated by quantum chemistry SCC-DV-Xa method, and the reactivity of complexes has been analy...The electronic structures of several dinuclears and trinuclears of molybdenum containing thiolates complexes have been calculated by quantum chemistry SCC-DV-Xa method, and the reactivity of complexes has been analyzed in terms of the molecular orbital energy level diagrams, orbital characters and charge populations.展开更多
文摘利用电荷自洽离散变分Xα(SCC-D V-Xα)方法计算了钒基固溶体中钒氢反应前后钒及其氢化物(V H x,x=0,1,2)、假定原子簇模型V H 鄢x(x=1,2)和V H x'(x=0,1)的电子结构.结果表明:钒与氢气反应生成V H 时,化学效应和结构效应都使V 3d和H 1s轨道向低能量方向移动,氢化物V H 中V 3d和H 1s轨道重叠最多,V -H 之间的相互作用较强。V H 再与氢气反应生成V H 2时,结构效应使V 3d和H 1s轨道都向高能量方向移动,氢化物V H 2中V 3d和H 1s轨道重叠最少,V 和H 之间的相互作用较弱。氢化物V H 和V H 2中不仅存在离子性相互作用,而且还存在共价性相互作用.结构效应导致V H 2中V -H 键的共价性减弱,从而导致V H 2中V 和H 之间的相互作用减弱。氢化物V H 的费米能级比V H 2的低,说明V H 更稳定.
文摘The effect of equi weight electrostatic field on transesterification of MeCOOBu with EtOH in the presence of base catalyst in liquid phase was investigated. The conversion of forward reaction and backward reaction was slightly enhanced in the equi weight field ( E =1×10 5 V/m). SCC DV X α calculations showed that the HOMO energy level of CH 2O was decreased by about 9 6 eV in H + field, while increased by about 23 7 eV in O 2- field. It is concluded that the activation energy of the reaction in equi weight electrostatic field is almost the same as in free field, owing to the same potential energy change of the reactants, transition states and products. In the unequi weight electrostatic field, the negative charge center seems to be the active site for reactants or products, while the positive one seems to be the active site for transition states, resulting in great decrease in the activation energy.
基金Supported by the National Natural Science Foundation of China(No. 29703003).
文摘The geometries of imidazole and its derivatives were respectively optimized by using ab initio method, and the molecular orbital energy levels and the charge densities were obtained for their optimum geometries. The frontier orbital energy levels, and the net charges of N (1) atom and the imidazole ring of those molecules were obtained with ab initio and SCC-DV-Xα methods. It was found that the inhibition properties of those compounds change with the highest occupied molecular orbital energy levels, and the net charges of N (1) atom. We took four iron atoms on the crystal plane (100) of α-iron as the surface which was used to study the adsorption towards the inhibitors. The adsorption models of the inhibitor to be adsorbed on the Fe-cluster surface were optimized with SCC-DV-Xα method. It turns out that the most favorable model is that the inhibitor molecule is adsorbed on the Fe-cluster surface in an inclined state. The calculation shows that the stabilization energies of the systems are well correlated with the inhibition efficiencies.
文摘SCC-DV-X method was used for the theoretical calculation of heteropoly an- ion , [SiMoO40]4- . and heteropoly blue anions,[SiMo2 Mo10O40]6 and [SiMo4 Mo!; O' 1,-. Th. f.o.ti.. .ol...l.. orbital. , orbital e.e.gi.. , Fe.mi 1...l. , the o.- cupied numbers of basis functions , free valences , Mulliken populations and the fig- ure of the total density of states have been obtained. The theoretical analysis indi- cates that all the atoms in the anions participate in chemical reactions , but Oc and Od have higher chemical activities than other atonts , which is supported by the ex- perimental results. The heteropoly hue anions with the α-Keggin structure distort a little and the levels of valence orbitals demonstrate that [SiMo4 Mo8O40]8 can form a six-electron heteropoly blue anoint by accepting two electrons.
文摘The electronic structures of several dinuclears and trinuclears of molybdenum containing thiolates complexes have been calculated by quantum chemistry SCC-DV-Xa method, and the reactivity of complexes has been analyzed in terms of the molecular orbital energy level diagrams, orbital characters and charge populations.
