[CP2K-user] [CP2K:18774] VIBRATIONAL ANALYSIS

[Hana]

Hello Lucas and Krack,

Thanks for your comments. I have attached my input file (input.txt) for 
your notice. My system consists of a single ion pair (sys.xyz) with no 
periodic boundary condition and I use the GAPW method with a 400Ry cutoff 
(Upon convergence test, this cutoff gave me 1e-4 convergence threshold for 
the total energy). For the normal mode analysis I fix the atoms of one ion 
and just study the vibrations of the other one. Please let me know what you 
think.

Thanks!


On Friday, May 5, 2023 at 2:31:52 AM UTC-5 Lucas Lodeiro wrote:

> I put my 2 cents in the possibility that you are running your calculation 
> using PBC, so the normal modes are not projected out to extract the 
> translational and rotational modes. Also you probably use a "low cutoff" so 
> the noise (energy/gradient waves due to plane waves), when the numerical 
> derivatives are calculated through adjacent points, is important... then 
> the frequency of your translational and rotational modes are not close to 
> zero as expected.
>
> Regards - Lucas Lodeiro
>
> El jue, 4 may 2023 a las 12:36, Hana (<holi... at illinois.edu>) escribió:
>
>> Hello,
>>
>> I am trying to obtain the normal modes of my gaseous system which 
>> contains a molecule (N atoms). First I optimize the geometry of my system 
>> with a MAX_FORCE threshold of 0.0005. Second, in a further calculation, I 
>> use the following setting:
>>
>> &VIBRATIONAL_ANALYSIS
>>   INTENSITIES
>>   NPROC_REP 256
>>   DX 0.001
>>   &PRINT
>>     &PROGRAM_RUN_INFO ON
>>     &END
>>   &END
>> &END
>>
>> I get 3N frequency modes all of which are nonzero. However, I expect the 
>> analysis to exclude the rotation and translation and return zeros for the 
>> first six modes. Is there any explanation for this? Here is the output 
>> (cm^-1) for the first six modes: 26.89, 30.12, 36.90, 55.93, 68.51, 90.65
>>
>> Thanks!
>>
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>>
>

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&GLOBAL
  PROJECT IL
  RUN_TYPE VIBRATIONAL_ANALYSIS
  PRINT_LEVEL MEDIUM
&END GLOBAL

&FORCE_EVAL
  METHOD Quickstep
  &DFT
    BASIS_SET_FILE_NAME EMSL_BASIS_SETS
    POTENTIAL_FILE_NAME POTENTIAL
    WFN_RESTART_FILE_NAME res_file.wfn

    &PRINT
      &MOMENTS
        PERIODIC FALSE
      &END
    &END

    &MGRID
      NGRIDS 5 
      CUTOFF 400
      REL_CUTOFF 40
    &END MGRID

    &QS
      METHOD GAPW
      EPS_DEFAULT 1.0E-12
      EPS_PGF_ORB 1E-7
    &END QS

    &SCF
        SCF_GUESS RESTART
        MAX_SCF 60
        EPS_SCF 1.0E-8

        &OT
                PRECONDITIONER FULL_ALL
                MINIMIZER DIIS
                LINESEARCH 2PNT
        &END

        &OUTER_SCF
                MAX_SCF 20
                EPS_SCF 1.0E-8
        &END OUTER_SCF

    &END SCF

    &XC
      &XC_FUNCTIONAL BLYP
      &END XC_FUNCTIONAL
      &vdW_POTENTIAL
         DISPERSION_FUNCTIONAL PAIR_POTENTIAL
         &PAIR_POTENTIAL
           TYPE DFTD3
           PARAMETER_FILE_NAME dftd3.dat
           REFERENCE_FUNCTIONAL BLYP
         &END PAIR_POTENTIAL
      &END vdW_POTENTIAL
    &END XC

    &POISSON
        PERIODIC NONE !xyz
        POISSON_SOLVER WAVELET  !PERIODIC
    &END POISSON

  &END DFT

  &SUBSYS
    &CELL
      ABC [Angstrom] 30 30 30 
      PERIODIC NONE
    &END CELL
    &TOPOLOGY
      COORD_FILE_NAME IL.xyz
      COORD_FILE_FORMAT XYZ
      &CENTER_COORDINATES
      &END
    &END TOPOLOGY

    &KIND H
      BASIS_SET 6-311Gxx
      POTENTIAL ALL
    &END KIND

    &KIND C
      BASIS_SET 6-311Gxx
      POTENTIAL ALL
    &END KIND

    &KIND N
      BASIS_SET 6-311Gxx
      POTENTIAL ALL
    &END KIND

    &KIND F
      BASIS_SET 6-311Gxx
      POTENTIAL ALL
    &END KIND

    &KIND S
      BASIS_SET 6-311Gxx
      POTENTIAL ALL
    &END KIND

    &KIND O
      BASIS_SET 6-311Gxx
      POTENTIAL ALL
    &END KIND

  &END SUBSYS

&END FORCE_EVAL

&MOTION
  &GEO_OPT
    MAX_FORCE 0.000015
    MAX_ITER 1600
    OPTIMIZER BFGS
    &BFGS
    &END
  &END
  &CONSTRAINT
    &FIXED_ATOMS 
      LIST 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
    &END
  &END
&END

&VIBRATIONAL_ANALYSIS
  INTENSITIES
  NPROC_REP 256
  DX 0.001
  &PRINT
    &PROGRAM_RUN_INFO ON
    &END
  &END
&END