원문정보
Meaning and Definition of Partial Charges
초록
영어
Partial charge is an important and fundamental concept which can explain many aspects of chemistry. Since a molecule can be regarded as neclei surrounded by electron cloud, there is no way to define a partial charge accurately. Nevertheless, there have been many attempts to define these seemingly impossible parameters, since they would facilitate the understanding of molecular properties such as molecular dipole moment, solvation, hydrogen bonding, molecular spectroscopy, chemical reaction, etc. Common methods are based on the charge equalization, orbital occupancy, charge density, and electric multipole moments, and electrostatic potential fitting. Methods based on the charge equalization using electronegativity are very fast, and therefore they have been used to study many compounds. Methods to subdivide orbital occupancy using basis set conversion, relies on the notion that molecular orbitals are composed of atomic orbitals. The main idea is to reduce overlap integral between two nuclei using converted orthogonal basis sets. Using some quantum mechanical observables like electrostatic potential or charge multipole moments. Using potential grids obtained from wavefunction, partial charges can be fitted. these charges are most useful to describe intermolecular electrostatic interactions. Methods to using dipole moment and its derivatives, seems to be sensitive the level of theory, Dividing electron density using density gradient being the most rigorous theoretically among various schemes, bears best potential to describe the charge the most adequately in the future.
목차
1. 부분전하의 필요성
2. 전기음성도를 이용한 빠른 부분전하 계산
3. 오비탈(Orbital)을 활용한 부분전하
3.1 Mulliken population 분석[2]
3.2 Löwdin population 분석[3,4]
3.3 Natural population 분석 (NPA)[5]
4. 공간분할을 활용한 부분전하[6]
5. 다중전하모멘트를 활용한 부분전하[7]
6. 전위(electrostatic potential)를 활용한 부분전하[8]
7. 분자동력학 계산에 많이 사용하는 부분전하
7.1 RESP 부분전하[9]
7.2 AM1-BCC 부분전하[10]
8. 향후 전망
참고문헌