Department of Physics, Banaras Hindu University, Varanasi, India.
J Mol Model. 2011 Jun;17(6):1435-44. doi: 10.1007/s00894-010-0845-y. Epub 2010 Sep 19.
A new charge distribution is proposed for the amino acids where each atom is associated with two point charges while each bond center is associated with one point charge. Centroids of charges arising due to atomic orbital hybridization called hybridization-displaced charges (HDC) and those located at the atomic sites and bond centers obtained by a modified form of the Mulliken scheme were combined. The density matrix calculations required for this analysis were performed at the B3LYP/6-31G** level of density functional theory. The combination of HDC centroids with the modified Mulliken charges was found to yield dipole moments and surface molecular electrostatic potentials (MEP) of the amino acids in good agreement with those obtained by rigorous DFT calculations or those obtained using the MEP-fitted CHelpG charges. This study shows that the combination of HDC centroids with the modified Mulliken charges is significantly superior to the conventional Mulliken charges.
提出了一种新的氨基酸电荷分布，其中每个原子与两个点电荷相关联，而每个键中心与一个点电荷相关联。由于原子轨道杂化而产生的电荷的质心称为杂化位移电荷（HDC），并且通过Mulliken 方案的改进形式获得的位于原子位置和键中心的电荷被组合。为此分析所需的密度矩阵计算是在密度泛函理论的 B3LYP/6-31G** 水平上进行的。结果发现，HDC 质心与改进的 Mulliken 电荷的组合产生的氨基酸偶极矩和表面分子静电势（MEP）与通过严格的 DFT 计算或使用 MEP 拟合的 CHelpG 电荷获得的偶极矩和 MEP 非常吻合。这项研究表明，HDC 质心与改进的 Mulliken 电荷的组合明显优于传统的 Mulliken 电荷。
