双原子分子在金属表面的吸附和解离过程的研究是表面科学的重要内容之一。在汽车的催化式排气净化器和在核反应堆中，简单金属Be 可被用于吸收各种由含C，N，H 和O 等原子的分子组成的废气。因此研究双原子分子在Be 表面的吸附和解离性质就显得特别有实际意义。本文采用基于密度泛函理论的第一性原理方法，系统地研究了双原子分子N2、CO 和NO 分子在Be(0001) 表面的吸附和解离性质。通过计算吸附体系的势能面（PES），态密度分布和差分电荷密度分布等性质，得出如下结论：1. N2 分子很难吸附在Be(0001) 表面。N2 在Be 表面解离的最小能量路径是沿着hcp-x 通道，其解离势垒为4.12 eV。我们认为Be 表面并不利于清理N2分子，而通过有效地排出反应产物N2，其可用于汽车的催化式排气净化器。2. CO 分子在Be 表面的吸附需要克服一定的能量势垒。最稳定的吸附态是fcc-z1 通道的FZ 态，而top-z1 通道的TZ 态的吸附势垒最小。通过对体系电子结构进行计算分析，我们进一步发现在吸附过程中，电子从CO 的成键轨道转移到了Be 的s 和pz 态。而CO 的反键轨道与Be 的px 和pz 态有较强的杂化现象。3. 对NO 分子，在Be(0001) 表面沿top-z1，fcc-z1 和hcp-z1 通道都有相应吸附态存在，且没有吸附势垒。最稳定吸附态为hcp-z1通道的HZ 态。进一步的电子结构计算表明，吸附态时有电子从NO 分子的最高占据轨道转移到表面的Be 原子。

It is of great importance to study the adsorption and dissociation of diatomicmolecules on metal surfaces to meet many intrinsic academic interests. The Besurfaces need special attentions because they have long been used in nucleationreactors as air cleaners to adsorb many kinds of residue gases composed of C,N, H, and O atoms. A systematic study of the adsorption and dissociation ofdiatomic molecules on the Be surfaces is obviously needed.Using ¯rst principles calculations, we systematically study the adsorptionbehaviors of diatomic molecular N2, CO and NO on the Be(0001) surface, bycalculating the potential energy surfaces, PDOS and di®erence electron density.It is found that N2 molecules can not adsorb molecularly on the clean Besurface, and the dissociation energy barrier of N2 is estimated to be as large as4.12 eV. Our studies indicate that the Be surfaces can not be used as N2 cleaners,but might be used to drive out N2 molecules in automotive catalytic converters.We ¯nd that CO molecularly adsorbs on the Be surface with small energybarriers. The most stable adsorption state is found to be the one at the surfacefcc hollow site, and the one at the surface top site is the adsorption state thathas the smallest energy barrier. Based on careful electronic structures analysis,we further reveal that during the molecular adsorption, electrons transfer frombonding orbitals of CO to s and pz electronic states of Be, while the antibondingorbital of CO strongly hybridizes with px and pz electronic states of Be.For NO，we ¯nd that there are always molecular adsorption states alongthe top-, fcc- and hcp-z1 channels, without any energy barrier. The most stableadsorption state is found to be along the hcp-z1 channel. We further reveal thatduring the molecular adsorption, electrons transfer from the highest occupiedmolecular orbital (HOMO) of NO to electronic states of Be.