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jaychiujaychiu 

Problem of DMol3 scanning potential energy surface

Hello Dear MS users,
I try to calculate the energy of ethane C-C single bond breaking. I use DMol3 with functional GGA/PBE and basis set DND. The following is error in my output file.
 
  ####ERROR####
 There should be  1 Constraints but none found on OPT file!
 Peak memory usage: 218952 kB on current thread
 ... Calling mpi_abort ...
Errors from parallel task 3:

  ####ERROR####
 There should be  1 Constraints but none found on OPT file!
 Peak memory usage: 225020 kB on current thread
 ... Calling mpi_abort ...
Errors from parallel task 4:

  ####ERROR####
 There should be  1 Constraints but none found on OPT file!
 Peak memory usage: 212880 kB on current thread

How can I solve this problem? 

Thank you very
Best Answer chosen by jaychiu
Felix HankeFelix Hanke
Hi, 
this is getting way too complicated. Can I reiterate that Materials Studio does not support the DMol3 scan_pes task, there is no support for it, and we never promised that it works in any documentation.
Instead, we have a very powerful set of scripting tool, which allow you to do many more things than simply constraining single bond lengths and then having to sort through the outmol file in detail. 
I have written an example script that does exactly the calculation you are looking for and returns a study table with a summary of the results. The script and an appropriate input file is attached, feel free to add any particular property that I might have missed. 
All the best, 
Felix

All Answers

Felix HankeFelix Hanke
Hi, 
your question is difficult to answer from the information you provided - there are many different ways to do this calculation and quite a few of them involve constraints. 
I gather that somehow you managed to assign constraints in the input deck, but then DMol3 struggled to read them when required. 
Can you please post a full set of input/output files where this problem occurs?
Thanks, 
Felix
jaychiujaychiu
Thanks for your response.
The following is the input setting. And the file is output file.

# Task parameters
Calculate                     scan_pes
Opt_energy_convergence        1.0000e-006
Opt_gradient_convergence      8.5200e-004 A
Opt_displacement_convergence  9.5100e-004 A
Opt_iterations                500
Opt_max_displacement          0.0100 A
Initial_hessian               improved
Symmetry                      off
Max_memory                    2048
File_usage                    smart
Scan_option                   optimization
Scan_dim_1
Distance 1 2 0 0 1.528 2.528 21

# Electronic parameters
Spin_polarization             restricted
Charge                        0
Basis                         dnd
Pseudopotential               none
Functional                    pbe
Aux_density                   octupole
Integration_grid              medium
Occupation                    fermi
Cutoff_Global                 3.3000 angstrom
Scf_density_convergence       1.0000e-005
Scf_charge_mixing             2.0000e-001
Scf_iterations                50
Scf_diis                      6 pulay

# Print options
Print                         eigval_last_it

# Calculated properties

 
Felix HankeFelix Hanke
Hi, 
thanks, that certainly helped to figure out what's going on. To run this particular calculation anyway, please add the line 
opt_coordinate_system cartesian
to your .input file and it will work fine. 
All the best, 
Felix
jaychiujaychiu
Hi,
I add the line to my input file, but it still can't run.
The following is the error in my output file.
 INPUT_DMOL error: unrecognized keyword(s): opt_coordinate_system          cartesian

Thanks,
Jay
Felix HankeFelix Hanke
Hi, 
this seems strange, the keyword is spelled correctly - but please refer to the keyword documentation if you are unsure. 
The only thing I can think of is that you may inadvertently have put the line into a keyword block where it was expecting a follow-up keyword blank line (for example for your PES scan block). Ideally, this keyword needs to be part of the other opt_ ... keywords, then it should work fine. 
If that is not the case, please post the entire input file and I will have a look. 
Best, 
Felix
jaychiujaychiu
I have tried many location. The error still exists. 
The file is my input file.

Thanks,
Jay
Felix HankeFelix Hanke
Hi, 
I fully admit that the error messages you get are not overly helpful, and I am not sure what one could do about that. However, if you remove the ` character from the very first line of your input file it should start to work again. 
Best, 
Felix
jaychiujaychiu
Hi,
After I remove the character, the result has no change. 
It still can't recognize the keyword 
opt_coordinate_system       cartesian

Thanks,
Jay
Felix HankeFelix Hanke
Hi, 
the attached input file appears to work fine for me.
Best, 
Felix
jaychiujaychiu
Hi,
I have tried version 7.0 and 2017 R2. However, both of them get the same error. Can you tell me which version you are using?
Thanks for your advise.

Best,
Jay
Felix HankeFelix Hanke
Hi, 
this is getting way too complicated. Can I reiterate that Materials Studio does not support the DMol3 scan_pes task, there is no support for it, and we never promised that it works in any documentation.
Instead, we have a very powerful set of scripting tool, which allow you to do many more things than simply constraining single bond lengths and then having to sort through the outmol file in detail. 
I have written an example script that does exactly the calculation you are looking for and returns a study table with a summary of the results. The script and an appropriate input file is attached, feel free to add any particular property that I might have missed. 
All the best, 
Felix
This was selected as the best answer
jaychiujaychiu
Hi Felix,
Thanks for your help and script.
The job can work after using the script.

Bests,
Jay