Author Topic: aoforce with D3 gives non-sensical IR intensities  (Read 263 times)

resofidentity

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aoforce with D3 gives non-sensical IR intensities
« on: February 09, 2017, 10:29:29 am »
Hello TM users,

I have calculated frequencies at RI-PBE0/def2-TZVPP and RI-PBE0-D3/def2-TZVPP lot for a 32 atoms molecule, while energies and geometries and frequencies seem to change reasonable upon usage of D3 I get huge/non-sensical changes in the IR-intensities most significant for C-H modes, for example:

left half without D3, right half including D3:
Code: [Select]
   
    78        a            3041.56         7.98263       YES     YES     78        a            3040.56      6960.93826       YES     YES
    79        a            3043.04        41.39996       YES     YES     79        a            3041.94      6448.59775       YES     YES
    80        a            3043.67         0.00138       YES     YES     80        a            3042.56         0.00525       YES     YES
    81        a            3049.32        23.88005       YES     YES     81        a            3048.54     32137.07152       YES     YES
    82        a            3049.43         0.00006       YES     YES     82        a            3048.64         0.48042       YES     YES
    83        a            3058.20         9.09133       YES     YES     83        a            3054.68     25764.48310       YES     YES
    84        a            3058.25         0.00376       YES     YES     84        a            3054.74         8.06161       YES     YES
    85        a            3101.47         0.00048       YES     YES     85        a            3100.32         0.03744       YES     YES
    86        a            3101.68         6.77616       YES     YES     86        a            3100.52       514.98364       YES     YES
    87        a            3101.95        15.37643       YES     YES     87        a            3100.98       906.86783       YES     YES
    88        a            3102.28         0.00068       YES     YES     88        a            3101.29         0.02734       YES     YES
    89        a            3139.02         0.00111       YES     YES     89        a            3139.50         0.18533       YES     YES
    90        a            3139.05         9.94201       YES     YES     90        a            3139.54       445.87550       YES     YES
    91        a            3146.14        11.68804       YES     YES     91        a            3146.80       723.37056       YES     YES
    92        a            3146.15         0.00783       YES     YES     92        a            3146.82         0.87743       YES     YES
    93        a            3149.96         0.00051       YES     YES     93        a            3151.92         1.48549       YES     YES
    94        a            3150.05         9.53521       YES     YES     94        a            3152.03       760.73230       YES     YES
    95        a            3158.68         8.78574       YES     YES     95        a            3153.04       565.26792       YES     YES
    96        a            3158.84         0.00182       YES     YES     96        a            3153.25         0.04004       YES     YES

Any idea what might be the problem?
Cheers
 R

gunnar.schmitz

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Re: aoforce with D3 gives non-sensical IR intensities
« Reply #1 on: February 10, 2017, 10:24:29 am »
Hi,

only from the frequencies it is hard to guess what might had happened. One small thing. You are using the RI approximation and hybrid functionals in aoforce. This is not recommended since the RI approximation will be switched off for some parts. I don't believe that this is the issue here since the intensities are related to derivatives of the dipole moment. But at least you could check what happens if you switch of the RI approximation (Then do a dscf call) and then run aoforce again.

Probably you should contact the Turbomole support.

uwe

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Re: aoforce with D3 gives non-sensical IR intensities
« Reply #2 on: February 13, 2017, 03:46:59 pm »
Hi,

not sure what happens here, but it might help to keep the Hessian (the frequencies seem OK, so the Hessian should be OK too) and to redo just the frequency analysis (which takes less than a second):

$drvopt
  ... other options here ...
  frequency analysis only


Then change some settings to check the effect.

But as gunnar.schmitz wrote: DFT-D does not alter the intensities directly, they only depend on the dispersion term via the geometry.

Uwe

christof.haettig

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Re: aoforce with D3 gives non-sensical IR intensities
« Reply #3 on: February 15, 2017, 03:27:30 pm »
It looks suspicous. If it is reproducible, you should send the input and output files to your TURBOMOLE provider so that they can check if it is a bug.