摘要
采用完全活性空间自洽场方法(CASSCF)以及组合的量子化学ONIOM方法,研究了硝基甲烷受限于椅式(5,5)单壁碳纳米管内的结构及热解过程。分子结构分析表明,椅式(5,5)碳纳米管内的硝基甲烷其构型发生扭转,Cs对称性消失,C—N键长略微缩短。热解势能面分析发现,硝基甲烷单体沿C—N键的热解是一个无过渡态的解离过程,而硝基甲烷在椅式(5,5)碳纳米管内的热解需经历一个过渡态,所需克服的能垒约为198kJ·mol-1,比硝基甲烷单体的解离能降低了21kJ·mol-1左右。此外,计算结果还表明,椅式(5,5)碳纳米管内的硝基甲烷热解过程中的分子结构、NO和CH基团电荷变化与单体解离过程亦有所不同。
The molecular structures and thermal decomposition of nitromethane confined inside a armchair （5,5） single-wall carbon nanotube were studied by using the complete active space self-consistent field （CASSCF） and ONIOM level of theory. Results show that nitromethane confined inside a CNT （5,5） has no Cs symmetry and the C--N bond becomes short slightly. Analysis of the potential energy curves along the C--N bond length shows that a transition state exists for the thermal decomposition of nitromethane/ CNT（5,5）, which is different from that of nitromethane monomer （no transition state for the C--N bond dissociation）. For nitromethane/CNT（5,5） ,the energy barrier of the transition state is calculated to be about 198 kJ·mol^-1, which is about 21 kJ·mol^-1 lower than that of the C--N bond dissociation energy of nitromethane monomer. In addition, calculated results show that the （5,5） single-wall carbon nanotube has effect on the changing in the molecular structure and electronic charge of NO2 and CH3 groups during the thermal decomposition process of nitromethane.
出处
《含能材料》
EI
CAS
CSCD
北大核心
2009年第5期518-522,共5页
Chinese Journal of Energetic Materials
基金
教育部科学技术研究重点项目(批准号:209080)
湖北省杰出青年基金项目(批准号:2008CDB261)
关键词
物理化学
碳纳米管
硝基甲烷
热解反应
从头算
physical chemistry
carbon nanotube
nitromethane
thermal decomposition
ab initio
