Convergence Error in CASPT2 calculation

tararia · 2017-06-28 20:05:43

Hi,
I am trying to run MS-CASPT2 calculation on the excited state of small actinide molecule. Surprisingly, though ground state CASPT2 finishes perfectly, excited state CASPT2 step ends up with the error:
Input :

CASPT2 &END
MaxIterations
100
IPEA
0.35
SHIFT
0.25
IMAGINARY
0.18
FROZEN
39
MULTISTATE
112
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112
NOMULT

Output error :

Maximal available memory for Molcas = 8388607992
---------------------------------------------------------------------------------------------
  Nr.    Label          Type            Offset          Length     Atime          Address
---------------------------------------------------------------------------------------------
  1     CASPT2          INTE           5196920             8           5        [0x3539540]
---------------------------------------------------------------------------------------------
Maximal available memory for Molcas = 8388607992
---------------------------------------------------------------------------------------------
  Nr.    Label          Type            Offset          Length     Atime          Address
---------------------------------------------------------------------------------------------
  1     CASPT2          INTE           3881394             8           5        [0x2b2ff10]
---------------------------------------------------------------------------------------------
Maximal available memory for Molcas = 8388607992
--- Stop Module:  caspt2 at Wed Jun 28 16:09:59 2017 /rc= _NOT_CONVERGED_ ---
--- Module caspt2 spent 1 hour and 45 minutes

    Convergence problem!

    ...................................................................................................
    ...................................................................................................
    .....If the computer should turn out to be wrong, the situation is still not alarming. The type....
    .....of obsessional error he may be guilty of is not unknown among the latest generation of HAL....
    .....9000 computers. It has almost always revolved around a single detail, such as the one you.....
    .....have described, and it has never interfered with the integrity or reliability of the..........
    .....computer's performance in other areas.........................................................
    ...................................................................................................
Non-zero return code - check program input/output
--- Stop Module:  auto at Wed Jun 28 16:09:59 2017 /rc= _NOT_CONVERGED_ ---
--- Module auto spent 1 hour and 45 minutes

Please help me out.

regards
tulika

Ignacio · 2017-06-29 08:16:03

Well, that's not MS-CASPT2, since you have NOMULT, you are just requesting 112 SS-CASPT2 calculations. I wouldn't use both SHIFT and IMAGINARY, the latter only should be enough in most cases. Difficult convergence could be a sign of poor reference (CASSCF) function, you may need to increase the active space, or just force CASPT2 convergence (increase iterations, loose threshold) and see if there are intruder states that could give you a hint.

tararia · 2017-06-29 09:48:55

Hi,
I am sorry by mistake I wrote MS-CASPT2 in the first phrase after which i followed CASPT2 only, thanks for your help. I would follow your instruction and try to execute. On this note, I would like to mention that that to check the accuracy, I have tried to run the same CASPT2 calculation with 41 SS-CASPT2 states with the similar active space (as for 112 SS-CASPT2 calculations), and the calculations ended up normally without any convergence issue. What does this indicate ?
Please help me out with your invaluable suggestions.

regards
tulika

tararia · 2017-06-29 11:37:58

Hi,
Could you please help me out in resolving the following error encountered:
output error part :

 ###############################################################################
 ###############################################################################
 ###                                                                         ###
 ###                                                                         ###
 ###    Location: AixCheck                                                   ###
 ###                                                                         ###
 ###                                                                         ###
 ###    Active unit: CHRED , should have been closed!                        ###
 ###                                                                         ###
 ###                                                                         ###
 ###############################################################################
 ###############################################################################
 ###############################################################################
 ###############################################################################
 ###                                                                         ###
 ###                                                                         ###
 ###    Location: AixCheck                                                   ###
 ###                                                                         ###
 ###                                                                         ###
---------------------------------------------------------------------------------------------
  Nr.    Label          Type     ###    Active unit: CHVEC1 , should have been closed!                       ###
 ###                                                                         ###
 ###                                                                         ###
 ###############################################################################
 ###############################################################################
 ###############################################################################
        Offset          Length     Atime          Address
---------------------------------------------------------------------------------------------
 ###############################################################################
 ###                                                                         ###
 ###                                                                         ###
 ###    Location: AixCheck                                                   ###
 ###                                                                         ###
 ###                                                                         ###
  1     CASPT2          INTE           3981104             8           5        [0x2bf2b00]
---------------------------------------------------------------------------------------------
Maximal available memory for Molcas = 8388607992
 ###    Active unit: CHORST , should have been closed!                       ###
 ###                                                                         ###
 ###                                                                         ###
 ###############################################################################
 ###############################################################################
 ###############################################################################
 ###############################################################################
 ###                                                                         ###

thanks

Molcas Forum

Announcement

#1 2017-06-28 20:05:43

Convergence Error in CASPT2 calculation

#2 2017-06-29 08:16:03

Re: Convergence Error in CASPT2 calculation

#3 2017-06-29 09:48:55

Re: Convergence Error in CASPT2 calculation

#4 2017-06-29 11:37:58

Re: Convergence Error in CASPT2 calculation

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