How to calculate the N2+(2_Pi_u state)

[Eric]

Hi, I want to calculate both N2+(2_sigma_g) and N2+(2_Pi_u). But I don't know how to build the input file for the second case.

This is my input file for N2+(2_sigma_g), which is the ground state. So this input file should be enough right?

start N2_2Sigmag

 title "N2_2Sigmag in aug-cc-pvdz basis set " 

geometry units au

  N  0.50000000 0.00000000 0.00000000

  N  -0.50000000 0.00000000 0.00000000

end

basis 

 * library aug-cc-pvdz 

end 

dft 

 odft 

 MULT 1 

 XC slater vwn_5 

 decomp 

end 

task dft optimize 

task dft frequencies

[Eric]

I tried to use TDDFT to calculate N2+(2_Pi_u). But I got an error. May I ask how to fix this problem and do the calculation correctly?

[Edoardo Aprà]

The error message is telling you that the D4h point group that your molecule belongs to is non-abelian,
therefore the TDDFT code -- that exploits abelian symmetry -- cannot cope with it.

The fix is to choose an abelian point group that is a subset of D4h.

http://symmetry.jacobs-university.de/cgi-bin/group.cgi?group=604&option=4

I choose D2h, and this requires to add the line symmetry c2h in the geometry input section,
as shown below

geometry units au
  N   0.50000000 0.00000000 0.00000000
  N  -0.50000000 0.00000000 0.00000000

  symmetry d2h
 end

https://nwchemgit.github.io/Special_AWCforum/st/id1038/How_to_calculate_polarizability.html

[Shuyang Ye]

Thank you for your help! 

Edoardo Aprà <edoard...@gmail.com>于2020年10月26日 周一下午9:02写道：

--


You received this message because you are subscribed to the Google Groups "NWChem Forum" group.


To unsubscribe from this group and stop receiving emails from it, send an email to nwchem-forum...@googlegroups.com.


To view this discussion on the web visit https://groups.google.com/d/msgid/nwchem-forum/193a6faf-0c16-44fe-9284-6958f1d49633o%40googlegroups.com.

[Eric]

Dear Sir,

I used your input file, there are still errors:

tddft_grad_init:                failed to read iroots                   0

 ------------------------------------------------------------------------

 ------------------------------------------------------------------------

  current input line : 

     0: 

 ------------------------------------------------------------------------

 tddft_grad_init:                failed to read iroots                   0

 ------------------------------------------------------------------------

 ------------------------------------------------------------------------

  current input line : 

     0: 

 ------------------------------------------------------------------------

 ------------------------------------------------------------------------

 An error occured in the Runtime Database

 tddft_grad_init:                failed to read iroots                   0

 ------------------------------------------------------------------------

 ------------------------------------------------------------------------

  current input line : 

     0: 

 ------------------------------------------------------------------------

 ------------------------------------------------------------------------

 An error occured in the Runtime Database

 ------------------------------------------------------------------------

 tddft_grad_init:                failed to read iroots                   0

 ------------------------------------------------------------------------

 ------------------------------------------------------------------------

  current input line : 

    22: task TDDFT optimize

 ------------------------------------------------------------------------

 ------------------------------------------------------------------------

 An error occured in the Runtime Database

 ------------------------------------------------------------------------

 For more information see the NWChem manual at https://github.com/nwchemgit/nwchem/wiki

 For further details see manual section:                                                                                                                                                                                                                                                                

 ------------------------------------------------------------------------

 For more information see the NWChem manual at https://github.com/nwchemgit/nwchem/wiki

 For further details see manual section:                                                                                                                                                                                                                                                                

 ------------------------------------------------------------------------

 An error occured in the Runtime Database

 ------------------------------------------------------------------------

 For more information see the NWChem manual at https://github.com/nwchemgit/nwchem/wiki

 For further details see manual section:                                                                                                                                                                                                                                                                

 ------------------------------------------------------------------------

 For more information see the NWChem manual at https://github.com/nwchemgit/nwchem/wiki

 For further details see manual section:                                                                         

Thus I tried to add :

civecs

grad

   root 1

end

Still, errors occur:

tddft_diagon: A-B is not positive-definite; try TDA                   0

The log file is sttached.

Thank you again for your patience and precious time!

[Edoardo Aprà]

https://nwchemgit.github.io/Special_AWCforum/st/id476/A_error_about_tddft_diagon__A-B_....html

https://nwchemgit.github.io/Excited-State-Calculations.html#cis-and-rpa-the-tamm-dancoff-approximation