forcite of MS

[manbusenlinyuzuru]

Forcite is based on Molecular Dynamics which can research diffusion coefficient, radial distribution function (RDF/ CN, coordination number) and 回转半径. There are two important parameters, Forcefield (力场) and Ensemble (系综).

[manbusenlinyuzuru]

1. forcefiled including COMPSS, Dreiding, Universal, pcff, vcff
2. COMPASS, COMPASS II, COMPASS III are used to calculate organic and inorganic materials
3. Universal contians a lot of atom parameters, suitable for many types moleculars and materials.
4. pcff is about 糖类、脂类、核酸 while vcff is connected with 多肽 and 蛋白质

[manbusenlinyuzuru]

1. ensemble including NVE (微正则系综), NVT (正则系综), NPT (等温T等压P系综) and NPH (等压P等焓H系综).
2. NVT and NPT are usually used.
3. NPT can research diffusion behavior to obtain a most stable density of the systerm
4. NVT can research the adsorption behavior.

[manbusenlinyuzuru]

https://www.kryii.com/94.html

[manbusenlinyuzuru]

how to calculate CN? There are some important parameters should be calculate firstly.

1. 取样间隔数σ(r), can choose 0.02 or 0.05. the space bigger, the result is more specific.
2. 盒子平均体积V（Å^3）, forcite-analyse-cell parameters, you can obtain the cell length Å, now you can get the volume (Å^3)
3. 一个盒子内目标原子数, edit set-choose the atom you want-display style, then you will know the number of a certain atom
4. 原子密度ρ（个/Å*3）, 目标原子数/盒子体积
5. dN=4Π（r^2) ρ g(r) σ(r), pai is 3.1415926. r and g(r) can be gotten from excel.
6. CN(r)=∑0-r 4Π（r^2) ρ g(r) σ(r)