中文摘要：

基于密度泛函理论,模拟了单壁碳纳米管（SWNTs）对5种碱基的吸附作用.考察了SWNTs直径、电荷转移量、碱基最高占据分子轨道能（EHOMO）和最低未占据分子轨道能（ELUMO）与SWNTs吸附碱基的吸附能之间的关系.结果表明,随着SWNTs直径的增大,SWNTs吸附碱基的吸附能降低.SWNT（6,6）吸附5种碱基的最低吸附能Emin与由碱基转移到SWNTs的电荷转移量（Q）及碱基的EHOMO线性负相关,相关系数分别为-0.966和-0.804（P〈0.05）.吸附后SWNTs与碱基的前线轨道无重叠,且SWNTs电子结构未受影响,表明吸附行为属于物理吸附.

英文摘要：

Study on the interactions between carbon nanotubes and nucleic acid bases can elucidate the toxicological mechanism of carbon nanotubes. We simulated the adsorption of five nucleic acid bases on single-walled carbon nanotubes （SWNTs） based on the density functional theory. The relationships between the adsorption energy of the bases adsorbed on SWNTs surfaces and the SWNTs diameter, amount of charge transfer, and energy of the highest occupied molecular orbital （ EnoMo ） and the lowest unoccupied molecular orbital （ ELUMO ） of bases were investigated. The results show that the adsorption energy descends with increasing SWNTs diameters. The lowest adsorption energy Emi＂ for the base/SWNT （6,6） complex exhibits a negative linear correlation with the amount of charge transferred from bases to SWNTs （Q） as well as the EHOMO of the bases, with the correlation coefficients of - 0.966 and - 0. 804 （P 〈 0.05 ）, respectively. There is no mixing of the molecular frontier orbitals, and the electronic structures of the SWNTs are not affected after adsorption, indicating that the interaction between bases and SWNTs is physisorption.