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liurui

Member

Registered: 2024-04-18

Posts: 1

roaming reaction (T1/S0)roam (S0/S1)roam (T1/S1)roam optimization

Dear all, I am trying to calculate (T1/S0)roam, (S0/S1)roam and (T1/S1)roam for roaming reaction of nitrobenzene, but no these structures through geometric optimization all the time, I would like to consult how I should modify input to make it work properly and obtain the same structures with previous paper [DOI: 10.1039/d0cp02077j].

Through a thorough exploration of the system PEHs, performing a series of CASSCF MECP optimizations imposing restrictions in the C1N7 bond distance and re-evaluating the energies at the CASPT2 level, a new T1/S0 STC region featuring a detachment of the nitro group, hereafter (T1/S0)roam, has been characterized. The structure is also a S0/S1 conical intersection (CI) and T1/S1 STC, since the three states (S0, S1, and T1) are degenerate (Table 1). In the (T1/S0)roam region the CASSCF(16,13) S0 wave-function is mainly described by a single closed-shell configuration state function, while both S1 and T1
are mostly described by a single one-electron promotion from what can be recognized as the b2 orbital of the NO2 molecule to the s* orbital associated with the original CN bond in nitrobenzene (Fig. S10, ESI†).42 The SOC between S0 and T1 at the (T1/S0)roam geometry is 48 cm-1

Here is my input:

&GATEWAY
 coord=14 
 nitrobenzene
 C                 -0.20342400   -0.09288600    0.09800890
 C                  0.00652330   -1.25722000   -0.58106000
 C                  0.18176000   -1.19926000   -1.98502000
 C                  0.15133900    0.05781950   -2.62266000
 C                 -0.15272200    1.20163000   -1.91517000
 C                 -0.29733800    1.17933000   -0.52176600
 N                 -0.26723700    0.27407100    2.36788000
 O                 -0.27435900   -0.95750100    2.52781000
 O                  0.86164500    0.48634000    1.87991000
 H                  0.03363930   -2.22232000   -0.08691810
 H                  0.38452400   -2.08796000   -2.55013000
 H                  0.30355300    0.10772200   -3.69072000
 H                 -0.23875900    2.16609000   -2.43146000
 H                 -0.48914600    2.05020000    0.05310090
 basis = ANO-L-MB
 Group = NoSym
 Constraints
 a = Ediff 
 Values
 a = 0.000
 End of constraints
>>> EXPORT MOLCAS_MAXITER=500
>>> Do while
&SEWARD
>>> If ( Iter = 1 ) <<<
&SCF
>>> EndIf <<<
&RASSCF
Nactel = 10 
Ras2 = 10
Spin = 1
Inactive = 53
Charge= 0
CiRoot=2 2 1
Rlxroot=1
&ALASKA
PNEW
>>COPY $WorkDir/$Project.RunFile $WorkDir/RUNFILE2
&RASSCF
Nactel = 10 
Ras2 = 10
Spin = 3
Inactive = 53
Charge= 0
CiRoot=2 2 1
Rlxroot=1
&ALASKA
PNEW
&SLAPAF
>>> EndDo

the structure after optimization:

 O                 -3.73180600   -1.06267661   -0.44598944
 O                 -2.37478070    0.05481752   -1.95480864
 N                 -2.98163186   -1.25972063   -1.50477837
 C                 -0.59666908    1.45860004    0.89783004
 C                  0.67972248    1.59332618    0.16332013
 C                  1.42114823    0.45906175   -0.29747015
 H                  2.41927461    0.58504925   -0.86568208
 C                  0.87507268   -0.88441502   -0.04675520
 C                 -0.37122725   -1.11193088    0.66248621
 C                 -1.06696227    0.09614574    1.13255599
 H                 -1.18498535    2.39317781    1.24288642
 H                  1.10956338    2.52896929   -0.02266064
 H                  1.37172408   -1.57533274   -0.87311513
 H                 -0.83803357   -2.10765946    0.66402040

However, the structure obtained in the previous paper as follows:

 C                 -0.20342400   -0.09288600    0.09800890
 C                  0.00652330   -1.25722000   -0.58106000
 C                  0.18176000   -1.19926000   -1.98502000
 C                  0.15133900    0.05781950   -2.62266000
 C                 -0.15272200    1.20163000   -1.91517000
 C                 -0.29733800    1.17933000   -0.52176600
 N                 -0.26723700    0.27407100    2.36788000
 O                 -0.27435900   -0.95750100    2.52781000
 O                  0.86164500    0.48634000    1.87991000
 H                  0.03363930   -2.22232000   -0.08691810
 H                  0.38452400   -2.08796000   -2.55013000
 H                  0.30355300    0.10772200   -3.69072000
 H                 -0.23875900    2.16609000   -2.43146000
 H                 -0.48914600    2.05020000    0.05310090

So, I hope can solve how to revise the input file to obtain the structure in the previous paper. Thank you for your help.