有场和无场下高价乙炔阳离子的理论研究  

A Theoretical Study for the Highly Charged Cations of C_2H_2 with and without External Electric Fields

作　　者：常海波[1] 陈波珍[1] 何裕建[1] 

机构地区：[1]中国科学院研究生院化学与化学工程学院,北京100049

出　　处：《化学学报》2008年第3期308-314,共7页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.20673142;20333050);中国科学院院长基金(No.0521021T04)资助项目

摘　　要：使用(U)B3LYP方法,选用6-311++G(d,p)基组,研究了在无场和不同外加电场强度下高价乙炔阳离子[C2Hn2+(n=2,34)]的结构、稳定性以及去质子化解离反应.研究表明,在无场下,C2H22+和C2H32+是稳定的,但C2H42+不稳定,自发解离生成两个C+和两个H+,C2H24+的这种解离归因于库仑爆炸.当外加电场强度达到0.06a.u.时,C2H22+自发解离生成C2H++H+;而对于C2H32+,当外加电场仅为0.0075a.u.时,自发解离生成C2H2++H+.C2H22+和C2H32+在场中的这种自发解离被归结为场致解离.The hybrid density functional （U）B3LYP calculations with the 6-311 ＋ ＋G（d,p） basis set were carried out for exploring the structures, stabilities, and H^＋-loss dissociation potential energy curves of the C2H2^n＋ （n=2, 3, and 4） ions without external fields and at different external electric field intensities. Without external electric fields, our calculations indicate that the C2H2^2＋ and C2H2^3＋ ions are stable, and the C2H2^4＋ ion is unstable and spontaneously dissociates forming two carbon cations and two protons. The spontaneous dissociation of the C2H2^4＋ ion was attributed to Coulomb explosion. At the external electric field intensity of 0.06 a.u., the C2H2^2＋ ion becomes unstable and spontaneously dissociates to C2H^＋＋H^＋. But for C2H2^3＋, the field intensity of 0.0075 a.u. will make it spontaneously dissociate to C2H^2＋＋H^＋. The spontaneous dissociations of C2H2^2＋ and C2H2^3＋ in the external electric field were attributed to the field-assisted dissociation.

关 键 词：乙炔阳离子 密度泛函理论 场致解离 库仑爆炸 

分 类 号：O641.1[理学—物理化学]