二硼化钛电子结构的量子化学计算

Quantum chemistry calculation on titanium diboride crystal

采用离散变分Xα量子化学计算方法 ,研究了二硼化钛的化学键和价电子结构特征 ,并阐述了TiB2 陶瓷晶体结构、电子结构与其力学性能和电性能之间的关系。结果表明 :TiB2 晶体结构中包含了Ti2 + 与B-混合键、B-与B-间的σ键以及B-2 pπ电子构成的离域大π键 ;TiB2 晶体的导带和价带电子主要是由Ti3d和B2 p轨道的价电子构成 ,这些价电子通过离域大π键在电流的作用下可在TiB2 晶体中迁移。

Based on its structures of chemical bonds and valence electrons, titanium diboride has special physical and chemical properties. The chemical bonds and valence electrons structure features of TiB 2 crystal are studied by self-consistent-field discrete variational Xα method. The relationship between crystalline structure, electrons structure and mechanical, electric properties is discussed. It is shown that the chemical bonds consisting in TiB 2 crystal are mixing bond of Ti 2+ with B -, σ bond of B - with B - and π bond formed by 2pπ electrons of B -. The conducting band and valence band are mainly formed by the valence electrons locating in Ti3d and B2p orbits. These valence electrons can transmit in TiB 2 crystal under electric current through the π bond.