SCF 電子結構收斂 ► 若在這無法收斂 ► Oband DFT 要去動SCF相關的參數
- SCF over (每一移動一個原子，就算一次SCF)
- 算Force ►作用對象是原子
- 算Stress應力為0 ► 作用對象為cell
- BFGS若不收斂，則為GO state不收斂(但有SCF有收斂)
► 最常原因是因為E_cut不夠，尤其在動晶包 (請看Stress是否有小不下來的現象)
長晶包 ► 應力波
臨界阻泥震盪 ► 最快停下來
stress (應變=>伸長量) 長度變化量/參考長度(總長) => “沒有單位”
- tolerance ► Q:如何判斷他的值該設多少? A:還是要看計算什麼物性來做決定。
TPSD ► 2 points 兩點之意(始=>末)，若要做TPSD castep計算，則需把BFGS的字手動更改為TPSD。或者直接於GO more內做更改。
Real Lattice 是(直或橫)的為A、B、C向量，而是由 uA(向量)+vB(向量)+wC(向量)所組成。
! Real Lattice(A) !
! 2.5448282 -1.4697230 0.0001380 !
! -0.0004034 2.9387474 -0.0001380 !
! 0.0002992 -0.0005183 8.0000000 !
x Element Atom Fractional coordinates of atoms x
x Number u v w x
x C 1 0.666572 0.333428 0.449079 x
x C 2 0.333428 0.666572 0.550921 x
兩相減則為 0.814736 angstrom。 (這時才有單位)
DFT-D means Van-der_Waals.
lo-to ► 用於離子晶體計算，在左右移動上補計算
DFT ► 屬基態
constraint ► 適用於固定原子 (需打開勾選最下面)
restraint ► 適用於表面重構
BFGS delocalize internals自由度較小
計算極化率的時候，可先儲存file，再到Efield裡面task，刪去 phonon，留下 efield，再做計算較快
(metal不可點選 因為計算電場若使用金屬 會有電流產生)
電場做出來的極化率 沒分頻率 相當於極高頻
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Open-access collection of crystal structures of organic, inorganic, metal-organic compounds and minerals, excluding biopolymers.
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在 .param 檔案內底部增加一行
charge : 數目