标题: ORCA做CASSCF优化问题求助 [打印本页] 作者Author: 尚艳磊 时间: 2024-8-20 09:25 标题: ORCA做CASSCF优化问题求助 各位前辈们好，最近在学习用ORCA做CASSCF计算，遇到一些问题。
我有已经用DFT方法优化好的TS结构，但在用单参考态做单点能计算的时候这个TS的T1有点大，想做一个多参考态的验证计算。
选择（5,5）对应1个自由基轨道、C-N和O-O键的成键与反键轨道，高斯结构已附在结尾。
我首先在高斯里面用uhf/3-21g做了个uno初猜，然后在Multiwfn确认了轨道是我想要的顺序，接着在ORCA里面转换为了gbw文件。
为了保证在做CASSCF优化的时候轨道不会被旋转，我采用了如下的输入参数：
%pal nprocs 60 end
%maxcore 5000
%scf MaxIter 512 end
! 3-21g moread optTS NumFreq VeryTightSCF NoIter defgrid3 KDIIS
%moinp "TS-casscf-321g.gbw"
%scf Thresh 1e-12 Tcut 1e-14 end
%casscf nel 5 norb 5 end
但是总是优化不出来，有次终于5个YES达到结构优化收敛了，但是频率计算好像报错了
ORCA finished by error termination in CASSCF
Calling Command: /work/home/ac5qzwfvnn/orca503/orca_casscf TS-casscf_D00052.casinp.tmp >TS-casscf_D00052.lastscf
Check for CASSCF-logfiles
ORCA_NUMCALC: ORCA finished with an error in the energy calculation
ORCA finished by error termination in CASSCF
Calling Command: /work/home/ac5qzwfvnn/orca503/orca_casscf TS-casscf_D00026.casinp.tmp >TS-casscf_D00026.lastscf
Check for CASSCF-logfiles
ORCA_NUMCALC: ORCA finished with an error in the energy calculation
Please check TS-casscf.lastint.dpl52 for details
Please check TS-casscf.lastscf.dpl52 for details
Please check TS-casscf.lastint.dpl26 for details
Please check TS-casscf.lastscf.dpl26 for details
[file orca_numfreq/numfreq_utils.cpp, line 2106]: Skipping calculation . . .
[file orca_numfreq/numfreq_utils.cpp, line 2106]: Skipping calculation . .
查阅提示的文件，发现[file orca_casscf/orca_casscf.cpp, line 8170]: ERROR (ORCA_CASSCF): Convergence Failure. Retry with modified convergence settings!
似乎是SCF不收敛。然后在ORCA论坛发帖询问，得到答复是 it makes no sense to try a CASSCF optimization with noiter. You need to converge the wavefunction or you cannot get a proper gradient.