[DFTB-Plus-User] MD in singlet and triplet excited states

[nkarimov]

Hello,

I am trying to perform MD calculations in singlet and triplet excited 
states.
My test molecule is a neutral molecule of Acrylic Acid.
When I run the MD in S1 state, everything works fine.
Unfortunately, when I have tried to do the same in S2, the fragmentation 
of the molecule had a place and job was stopped with an Error message:
"Fractional fillings not currently possible for excited state property 
calculations"

Can I do something with this or it is a source code issue?

My input:

Driver = VelocityVerlet {
   MovedAtoms = 1:-1
   Steps = 10000
   TimeStep = 5
   Thermostat = None {
   InitialTemperature [Kelvin] = 300.0
   }
   OutputPrefix = "md_nvt_1.out"
}

Hamiltonian = DFTB {
   Charge = 0
   SpinPolarisation = {}
   SCC = Yes
   MaxSCCIterations = 250
   SCCTolerance = 1.0e-4
   Mixer = Broyden {
   MixingParameter = 0.3
   }
   Differentiation = Richardson {}
   SlaterKosterFiles = Type2FileNames {
     Prefix = "/export/home/nkarimov/DFTB/mio-1-1/"
     Separator = "-"
     Suffix = ".skf"
   }
   MaxAngularMomentum {
     C = "p"
     O = "p"
     H = "s"
   }
   Filling = Fermi {
     Temperature [Kelvin] = 300.0
   }
}

Options {}

ExcitedState = Casida {
   NrOfExcitations = 10
   StateOfInterest = 2
   Symmetry = 'singlet'
   WriteTransitions = Yes
   WriteSPTransitions = Yes
   WriteMulliken = Yes
   WriteCoefficients = Yes
   WriteEigenvectors = Yes
   WriteTransitionDipole = Yes

}

ParserOptions {
   ParserVersion = 5
}

Thanks,
Natalia Karimova

Assistant Research Scientist I
Chemistry Department
UC Irvine