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标题: VEES计算中可以设置占据轨道和非占据轨道数量吗 [打印本页]

作者
Author: halouhapily 时间: 2023-4-11 15:29
标题: VEES计算中可以设置占据轨道和非占据轨道数量吗
本帖最后由 halouhapily 于 2023-4-11 17:40 编辑

各位老师好：
我想用ORCA中的CIS计算体系的VEES，有没有什么方法可以设置在计算中考虑的占据轨道和未占据轨道的数量吗？

作者
Author: wzkchem5 时间: 2023-4-11 17:07
应该可以用冻结轨道（例如%method FrozenCore FC_EWIN end，然后在实际计算用的模块里用ewin关键词指定冻结的轨道的能量范围）的功能吧？也就是不是指定考虑哪些占据轨道和虚轨道，而是指定不考虑哪些占据轨道和虚轨道

作者
Author: halouhapily 时间: 2023-4-11 17:36
本帖最后由 halouhapily 于 2023-4-11 17:39 编辑

wzkchem5 发表于 2023-4-11 17:07
应该可以用冻结轨道（例如%method FrozenCore FC_EWIN end，然后在实际计算用的模块里用ewin关键词指定冻结 ...

%cis
...
OrbWin[0] = 2,-1,-1,14 # orbital window for spin-up MOs
OrbWin[1] = 2,-1,-1,16 # orbital window for spin-down MOs
end
The “-1” is in the above example mean that the HOMO and LUMO for the spin-.up and spin-down orbitals
will be automatically determined by the program. In other words, in the above example, only the following
excitations are included in the TDDFT calculation:
• Excitations from any occupied alpha orbital whose index is between 2 (inclusive) and that of the alpha
HOMO (inclusive), to any virtual alpha orbital whose index is between that of alpha LUMO (inclusive)
and 14 (inclusive)
• Excitations from any occupied beta orbital whose index is between 2 (inclusive) and that of the beta
HOMO (inclusive), to any virtual beta orbital whose index is between that of beta LUMO (inclusive)
and 16 (inclusive)
老师以上是我在手册里面找到的CIS方法里定义如何考虑轨道的另一种方法，但是我才疏学浅，没有理解他的意思，感觉他是将自旋向上向下分开考虑，如果是闭壳层，应该怎么写呢？
如果我想仅考虑10个占据轨道和10个未占据轨道，应该怎么设置呢？我按照下面的方法写的，但是出现报错
!RHF ZINDO/S TightSCF DIIS PrintBasis
%cis
Nroots 10
maxdim 100
Triplets true
OrbWin[0]=10,-1,-1,10
OrbWin[1]=10,-1,-1,10
end
%output
print[p_mos] 1
end
%pointcharges "ex.pointcharge"
* xyz -3 1

报错：
WARNING (orca_cis): NRoots > NCSFs. Resetting to NCSFs
WARNING: DavidsonBuffer called with NCI=-10878!!!!
WARNING: DavidsonBuffer called with NVECS=-21756!!!!
Error (ORCA/VECTOR): Negative vector size! (VectorLength=-10878)

作者
Author: wzkchem5 时间: 2023-4-11 18:08

halouhapily 发表于 2023-4-11 10:36
%cis
...
OrbWin[0] = 2,-1,-1,14 # orbital window for spin-up MOs

手册已经写得很清楚了，当写OrbWin[0] = 2,-1,-1,14的时候，表示alpha轨道的跃迁只考虑"Excitations from any occupied alpha orbital whose index is between 2 (inclusive) and that of the alpha
HOMO (inclusive), to any virtual alpha orbital whose index is between that of alpha LUMO (inclusive)
and 14 (inclusive)"
那么假如你写OrbWin[0]=10,-1,-1,10，就表示你只考虑"Excitations from any occupied alpha orbital whose index is between 10 (inclusive) and that of the alpha
HOMO (inclusive), to any virtual alpha orbital whose index is between that of alpha LUMO (inclusive)
and 10 (inclusive)"
显然后者不是“考虑10个占据轨道和10个未占据轨道”的意思

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