Restarting MCSCF calculation with different basis

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ankit7540
Posts: 46
Joined: 05 Sep 2015, 10:49
First name(s): ANKIT
Last name(s): RAJ
Affiliation: National Chiao Tung University
Country: Taiwan, Province of China

Restarting MCSCF calculation with different basis

Post by ankit7540 » 08 May 2020, 07:16

I am trying to rerun a RASSCF calculation with two basis sets for N2. The first calculation goes from HF-> MP2-> RASSCF with the basis cc-pVTZ (this is as suggested on my previous question (viewtopic.php?f=9&t=1074). I obtain the output along with the SIRIUS.RST and SIRIFC files.

Now I would like to restart the same with aug-cc-pVTZ basis.

I tried, passing SIRIUS.RST to the new input, as following,

Code: Select all

*ORBITAL INPUT
.MOSTART
NEWORB
and received the error.

Code: Select all

                   .--------------------------------------------.
                   | Starting in Wave Function Section (SIRIUS) |
                   `--------------------------------------------'


Input ERROR in connection with ".MOSTART" of type    9
     NSYM, NBAS from input       :  8        19   11   11    5   19   11   11    5
     NSYM, NBAS from MOSTART file:  8        13    7    7    3   13    7    7    3
I was hoping the program could use orbital overlap scheme (so called projecting orbitals in MCSCF from prev results) to guess the initial occupation for the new larger basis based on the previous results. Any ways to achieve this in DALTON.

The two output files are attached.

Thanks.
Attachments
p_10e_RAS1_LR4_N2_augcTZ.out
trying to restart with a larger basis
(30.76 KiB) Downloaded 23 times
p_10e_RAS1_LR4_N2_cTZ.out
original calculation at smaller basis, N2
(74.15 KiB) Downloaded 28 times
Best regards.
Ankit

taylor
Posts: 576
Joined: 15 Oct 2013, 05:37
First name(s): Peter
Middle name(s): Robert
Last name(s): Taylor
Affiliation: Tianjin University
Country: China

Re: Restarting MCSCF calculation with different basis

Post by taylor » 08 May 2020, 14:25

I don't think you can "restart" with a different basis. I think the word is intended to be interpreted literally, as in picking up a calculation at the point where it has stopped (or died) and continuing it from there, possibly with a minor change to the input parameters.

I can imagine that projecting the previous calculation MOs onto the new atomic basis would give you a better starting guess and save maybe a few MCSCF iterations, but I am sceptical that the saving would be that great in terms of the overall computer time.

Best regards
Pete

ankit7540
Posts: 46
Joined: 05 Sep 2015, 10:49
First name(s): ANKIT
Last name(s): RAJ
Affiliation: National Chiao Tung University
Country: Taiwan, Province of China

Re: Restarting MCSCF calculation with different basis

Post by ankit7540 » 11 May 2020, 10:35

Thank you.
Best regards.
Ankit

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