摘要
用量子化学从头算MP2、QCISD、CCSD方法结合6-311++G(3df,3pd)基组的计算水平以及休克尔分子轨道(HMO)理论对基态NO2大π键进行了研究。结果显示,基态NO2中氮原子接近sp2杂化。未参与成键的杂化轨道电子占据数约为0.99。大π键中成键电子和反键电子总数均约为3.62;,而自然键轨道(NBO)理论计算出NO2分子中存在3中心4电子大π键,参与离域的电子总数约为3.98;HMO法计算表明,具有Π43键的NO2分子比存在Π33键的NO2分子能量低187.855 kJ/mol。故基态NO2分子中存在Π34键的说法更合理。
By means of quantum chemical ab initio MP2, QCISD, CCSD theory and Huckel molecular orbital （HMO） method, the delocalized π-bond of NO2 was studied. The calculation suggesed that the nitragon atom in ground-NO2 was sp2 hybridization. The none-bonding hybridized atomic orbital was occupyzed by 0. 99 electrons. Moreover, 3.62 electrons occupied the π- and π -bond. The natural bond orbital analysis indicated that 3. 98 electrons occupied a three-center four-electron w-orbital. The HMO study showed that the energy of NO2 system with П3^4 bond was lower than that with П3^4 bond by 187. 855kJ/mol. Thus at the ground state, the description of NO2 possessing a П3^4 bond was more reasonable.
出处
《贵州师范大学学报（自然科学版）》
CAS
2011年第4期76-79,共4页
Journal of Guizhou Normal University：Natural Sciences
基金
贵州省科学技术基金(黔科合J字[2009]2241号)
贵州师范大学博士启动基金
关键词
大π键
从头算
休克尔分子轨道法
三中心四电子键
角扩张
extended ,tr-bond
ab initio calculation
Huckel molecular orbital method
three-center four-electron hyperbond
orbital angle expansion
