从头算和ABEEMσπ/MM对(CH_3OH)_n(n=3～12)和[Na(CH_3OH)_n]^+(n=3～6)体系的研究

Studies of (CH_3OH)_n(n=3—12) and [Na(CH_3OH)_n]^+( n=3—6)via ab initio and ABEEMσπ/MM

采用从头算方法(ab initio)和原子-键电负性均衡浮动电荷分子力场方法(ABEEMσπ/MM),对甲醇团簇(CH_3OH)n(n=3~12)和[Na(CH_3OH)_n]^+(n=3~6)体系的结构、电荷分布和结合能进行研究.依据从头算结果构建上述体系的ABEEMσπ/MM浮动电荷势能函数,并确定相关参数.结果表明,ABEEMσπ/MM所获得的结构和结合能等均优于OPLS/AA力场,并与从头算结果相符,其中键长的平均绝对偏差(AAD)小于0.004 nm,键长、键角和结合能的相对均方根偏差(RRMSD)分别小于3.8%,1.7%和6.8%;电荷分布与从头算结果的线性相关系数均大于0.99.

The stable structures, charge distributions and binding energies of cyclic methanol cluster（ CH3OH）n（ n = 3—12） and [Na（ CH3OH）n]~＋（ n = 3—6） were studied via ab initio and the atom bond electronegativity equalization fluctuating charge force field（ ABEEMσπ/MM）. Based on the ab initio results,the ABEEMσπ/MM fluctuating charge potential function were constructed and the related parameters were determined for the above systems. The results show that the structures,binding energies and other properties from ABEEMσπ/MM are in consistent with the ab initio calculation,and better than the OPLS/AA force field. The average absolute deviation（ AAD） of bond length is less than 0. 004 nm,and the relative root mean square deviations（ RRMSDs） of bond length,bond angle and binding energy are less than 3. 8%,1. 7% and6. 8%,respectively. The linear correlation coefficients of the charge distributions of ABEEMσπ/MM and ab initio calculation are all above 0. 99.