Vibrational analysis for single atom


Clicked A Few Times
I'm trying to do some vibrational analyses to calculate free energies of some bond dissociation reactions. When I do some single atom anions however (Cl-, Br-), I get the following error:

  You want to calculate the vibrational frequencies for            1  atoms?
  Unfortunately this is not possible
 ------------------------------------------------------------------------
 vib_vib: bomb      911
 ------------------------------------------------------------------------
 There is an error in the input file
 ------------------------------------------------------------------------
 For more information see the NWChem manual at http://nwchemgit.github.io/index.php/NWChem_Documentation


 For further details see manual section:                                                                                                                                            
0:vib_vib: bomb:Received an Error in Communication
application called MPI_Abort(comm=0x84000000, 911) - process 0


This is the input:

start job

title "Chloride anion"

geometry
 Cl                    0.00000000     0.00000000     0.00000000
end

charge -1

basis
  * library 6-311G**
end

dft
  xc m06-2x
  iterations 50
end

freq
  temp 7 273.15 298.15 323.15 373.15 423.15 453.15 473.15
  animate
end

task dft energy
task dft freq


Am I doing something wrong or is this simply not possible?

Forum Vet
Nuclear displacements
Ivo,
I am not quite sure anybody has figured out yet how to calculate the nuclear displacements of a single atom.

Clicked A Few Times
I understand that the vibrational analysis itself cannot be done in a meaningful way, but it would be useful if the program still did the thermochemistry.
I managed to do it by hand now, but since I don't calculate translational entropies on a daily basis, it took me while to figure out how to do it.


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