Problems in DIIS Convergence

Find answers or ask questions regarding Dalton calculations.
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edulsa
Posts: 5
Joined: 11 Nov 2013, 18:41
First name(s): Eduardo
Middle name(s): Lemos de
Last name(s): Sa
Affiliation: Dep. Quimica, Universidade Federal do Parana
Country: Brazil

Problems in DIIS Convergence

Post by edulsa » 06 Nov 2018, 16:56

Dear

I am trying to calculate the optical rotation of an organic compound (C, H, O and Br) starting from x-ray crystallographic data (output is attached). Firstly, I didn't get SCF convergence using default cycles number. To work around this, I rose step number until 1024 (I know, it is a very high value and normally, this wouldn't be needed). But, my problem now is that the calculation is stopped due, I guess, a full storage in scratch partition. In the beginning, there were 325 GB available but file AOTWINT is a 324 GB long. A previous calculation with a molecule of the same size (but without BR) ran smoothly.
Please, I will appreciate any hints to solve this: they can be about how to get the best convergence faster or how to store integrals in RAM memory (I have 16 GB) instead of store them in a hard disk.

Thank you in advance

Yours

Eduardo

Dep. Química da Universidade Federal do Paraná - Curitiba - Brazil
Attachments
content.log
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cort-opt.dalton.log
(4.24 KiB) Downloaded 3 times
cort-opt.out
(34.49 KiB) Downloaded 4 times

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magnus
Posts: 431
Joined: 27 Jun 2013, 16:32
First name(s): Jógvan Magnus
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Affiliation: Hylleraas Centre, UiT The Arctic University of Norway
Country: Norway

Re: Problems in DIIS Convergence

Post by magnus » 06 Nov 2018, 21:24

You need to run a direct calculation so that two-electron integrals are recomputed when needed and not stored on disk. To do this, add a .DIRECT keyword under the **DALTON INPUT section.

I also note that you have a **SCF INPUT but this section should be added under **WAVE FUNCTION and as *SCF INPUT and not **SCF INPUT. Also I don't think you need such a tight threshold in the SCF, especially considering that you're using a slightly higher than default threshold in the **PROPERTIES part.

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