从头计算研究乙酰胆碱构象和分子静电势

在Hartree－Fock和二级Moller－Plesset微扰理论MP2水平，用6－31G对乙酰胆碱进行了从头计算研究，发现了旁式和反式两种稳定构象．经零点振动能校正后，在Hartree－Fock级别旁式较反式稳定0．24kJ·mol~(-1)；而在MP2级别，反式较旁式稳定2．07kJ·mol~(-1).谐振动频率在HF／6－31G水平计算.还给出了两种构象的MP2分子静电势图.

Ab Initio Study on the Conformation and Molecular Electrostatic Potentials of the Acetylcholine

All-electron ab initio calculations of acetylcholine (Ach) ion have been carried out at the Hartree-Fock and the second order Moller-Plesset perturbation theory MP2 levels using 6-31G* basis set. Two stable conformations of gauche and trans forms of Ach have been found. It was found that after zero-point vibrational energy ZPVE corrections, at the Hartree-Fock level the gauche form is 0.24 kJ•mol-1 more stable than the trans, but at MP2 level the trans is 2.07kJ•mol-1 more stable than the gauche. The Harmonic vibrational frequencies have been computed at HF/6-31G* level. The Molecular Electrostatic Potentials, MEP contour maps of two conformations of the Ach based on MP2 wavefunctions are shown in this article.