数值模拟在材料工程中的应用讲述.pptx

Oxygenation mediating the valence density-of- states and work function of Ti(0001) skin 肖晨 材工三 ABSTRACT Consistency between density function theory calculations and photoelectron spectroscopy observations confirmed predictions based on the framework of bond-band-barrier (3B) correlation notation [Sun, Prog. Mater. Sci., 2003, 48, 521–685] that an oxygen adsorbate interacts with Ti(0001) skin atoms to form a tetrahedron with creation of four valence density-of-state features: O–Ti bonding electron pairs, O nonbonding lone pairs, Ti electronic holes, and Ti antibonding dipoles. Formation of the dipoles low- ers the work function of the Ti(0001) skin and electron–hole generation turns the metallic Ti(0001) into the semiconductive O–Ti(0001). Findings confirm the universality of the 3B correlation in understanding the dynamics of oxygen chemisorption and the associated valence electrons involved in the process of oxidation. density-of-states (DOS) 固体物理中的重要概念，即能量介于E[1]??～E+△E之间的量子态数目△Z与能量差△E之比，即单位频率间隔之内的模数。N-E关系反映出固体中电子能态的结构，固体中的性质如电子比热，顺磁磁化率等与之关系密切。在技术上，可利用X射线发射光谱方法测定态密度。对自由电子而言，N(E)=4πVEl/2(2m)3/2/h3，式中V为晶体体积，h为普朗克常数，m为电子质量。 Principle: bond–band–barrier (3B)correlation DFT calculations Integrations in the Brillouin zone were performed using special k-points generated with a 15*15*15 mesh parameter grid for the Ti primitive cell and 6*6*1 for both the surface and interlayers of the Ti(0001). The structural optimization was performed until the energy change per atom was less than 5*10-7 eV, the forces on atoms were less than 0.01 eV ?-1, all the stress components were less than 0.02 Gpa and a maximum displacement of 5.0 *10-4 ? was reached. The following formulates the adsorption energy: Fig. 2 shows the possible chemisorption sites. Average adsorption energy The results in Table 1 indicate the following. Firstly, for the monolayer adsorption model, the FCC site is energetically more favorable than the hexagonal close-packed (HCP) sites and the interlayer sites from