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[求助]
用高斯搜索過渡態(tài)反應(yīng)物和產(chǎn)物自旋多重度不一樣怎么辦?
如題,用高斯搜索過渡態(tài),反應(yīng)物自旋多重度為1,產(chǎn)物自旋多重度為5,過渡態(tài)自旋多重度應(yīng)該怎么設(shè)?我設(shè)自旋多重度為1搜到過渡態(tài)后,跑IRC很容易搜到反應(yīng)物,但是怎么跑到自旋多重度為5的產(chǎn)物很迷惑,我可以用過渡態(tài)的結(jié)構(gòu)把自旋多重度改為5來進(jìn)行計(jì)算嗎?這是否意味著我的結(jié)構(gòu)在過渡態(tài)瞬間電子結(jié)構(gòu)改變?這樣做對(duì)嗎?
附上計(jì)算腳本
1.先掃描鍵長
#p opt=modredundant b3lyp/gen geom=connectivity pseudo=read scfcyc=200 symm=veryloose
Fe(H2B(pz)2)2phen_2 6-31g
0 1
Fe 0.00000000 0.00000000 2.62521400
S -1.24849800 1.31269500 -6.46666200
S 1.24849800 -1.31269500 -6.46666200
N -1.25380300 0.39111200 1.08503100
分子坐標(biāo)好長,不寫了
2.找到可能的過渡態(tài),計(jì)算頻率
#p freq ub3lyp/gen pseudo=read scfcyc=200 symm=veryloose
Fe_phen_2freq
0 1
Fe 2.54767100 0.00002800 0.00002100
S -6.28746100 -2.17776300 0.42803200
S -6.28746900 2.17775800 -0.42805800
這里還是用自旋多重度=1計(jì)算的,結(jié)果發(fā)現(xiàn)只有1個(gè)-200的虛頻,很開心
3.人為把自旋多重度改為5進(jìn)行優(yōu)化計(jì)算,跑出來的結(jié)果跟產(chǎn)物很相像,但是有一個(gè)-8.71的虛頻,震動(dòng)方向如fig1紅色箭頭所示,我是否需要把它重新調(diào)關(guān)鍵詞優(yōu)化?要怎么調(diào)關(guān)鍵詞呢?可以直接沿震動(dòng)方向調(diào)坐標(biāo)優(yōu)化嗎?
#p opt freq=noraman ub3lyp/gen iop(3/24=1,5/13=1) pseudo=read symm=veryloose
ts1 6-31+g* optfreq
0 5
Fe 0.00000000 0.00000000 2.53767100
S 2.27317600 -0.66823400 -6.22746100
S -2.27317600 0.66823400 -6.22746100
4.分別跑IRC找產(chǎn)物和反應(yīng)物,問題來了
a)自旋多重度設(shè)為1找反應(yīng)物
#p irc=(CalcFC,forward,maxpoints=10,stepsize=20) b3lyp/gen
pseudo=read
ts1_irc forward
0 1
Fe 2.54767100 0.00002800 0.00002100
S -6.28746100 -2.17776300 0.42803200
S -6.28746900 2.17775800 -0.42805800
很順利結(jié)束
b)自旋多重度設(shè)為5找產(chǎn)物
#p irc=(CalcFC,reverse,maxpoints=30,stepsize=20,maxcycle=400) IOp(5/13=1) b3lyp/gen pseudo=read
ts1_irc reverse
0 5
Fe 2.54767100 0.00002800 0.00002100
S -6.28746100 -2.17776300 0.42803200
S -6.28746900 2.17775800 -0.42805800
各種報(bào)錯(cuò),各種調(diào)參數(shù),報(bào)錯(cuò)信息如下:
Cartesian Forces: Max 0.027937985 RMS 0.005666714
Z-matrix is all fixed cartesians, so copy forces.
Leave Link 716 at Wed Dec 9 11:03:35 2015, MaxMem= 4026531840 cpu: 1.0
(Enter /public/software/g09/l123.exe)
IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC
SCF convergence failure! Path Direction Number 1 Point Number 2
Unrecoverable SCF failure
Error termination via Lnk1e in /public/software/g09/l123.exe at Wed Dec 9 11:03:35 2015.
Job cpu time: 24 days 21 hours 43 minutes 58.5 seconds.
File lengths (MBytes): RWF= 17086 Int= 0 D2E= 0 Chk= 106 Scr= 2
求助各位大神
![用高斯搜索過渡態(tài)反應(yīng)物和產(chǎn)物自旋多重度不一樣怎么辦?]()
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