DFT vibrational analysis with symmetry

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afca
Posts: 19
Joined: 11 Nov 2013, 01:23
First name(s): Antonio
Last name(s): Arapiraca
Affiliation: CEFET/MG
Country: Brazil

DFT vibrational analysis with symmetry

Post by afca » 24 Jun 2015, 04:18

Hi,

I'm trying to do a geometry optimization with automatic detection of symmetry, but I get the error

--- SEVERE ERROR, PROGRAM WILL BE ABORTED ---
Date and time (Linux) : Sun Jun 21 18:05:42 2015


Reason: DFT analytical Hessians do not work with symmetry

I used the following input

Code: Select all

ATOMBASIS
benzene
using the basis 6-31G**
Atomtypes=2 Angstrom
Charge=6.0 Atoms=6 Basis=6-31G**
C1   0.000000    1.389400    0.000000
C2   1.203256    0.694700    0.000000
C3   1.203256   -0.694700    0.000000
C4   0.000000   -1.389400    0.000000
C5  -1.203256   -0.694700    0.000000
C6  -1.203256    0.694700    0.000000
Charge=1.0 Atoms=6 Basis=6-31G**
H7   0.000000    2.475300    0.000000
H8   2.143673    1.237650    0.000000
H9   2.143673   -1.237650    0.000000
H10  0.000000   -2.475300    0.000000
H11 -2.143673   -1.237650    0.000000
H12 -2.143673    1.237650    0.000000

**DALTON INPUT
.OPTIMIZE
**WAVE FUNCTIONS
.DFT
B3LYP
*SCF INPUT
.THRESH
1.0D-10
**PROPERTIES
.VIBANA
.QUADRU
.POLARI
.NQCC
**END OF DALTON INPUT
Can someone help me with this input configuration?

Best Regards
Antônio

bast
Posts: 1210
Joined: 26 Aug 2013, 13:22
First name(s): Radovan
Last name(s): Bast
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Country: Germany

Re: DFT vibrational analysis with symmetry

Post by bast » 24 Jun 2015, 18:06

it means that the DFT analytic Hessian cannot handle symmetry.
IMO the way out would be to specify a structure optimization algorithm
which does not explicitly compute the Hessian.
the other trivial option is to remove symmetry but this would
be a waste.

kennethruud
Posts: 252
Joined: 27 Aug 2013, 16:42
First name(s): Kenneth
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Affiliation: UiT The Arctic University of Norway
Country: Norway

Re: DFT vibrational analysis with symmetry

Post by kennethruud » 24 Jun 2015, 21:36

Please note that the little part of the output file that has been provided suggests that the geometry has converged, and the only reason a Hessian is requested is because the calculation requests a vibrational analysis. Thus, pick the last geometry, remove symmetry (NoSymmetry) and run just the vibrational analysis (.RUN PROPERTIES instead of .OPTIMIZE).

Kenneth

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