On Tue, Jun 21, 2011, Emmanuel Baribefe Naziga wrote:
>
> I am getting the following output from NAB for normal mode calculations. It
> prints just the frequencies with no other thermodynamic data.
>
> Order of the Hessian matrix 3672
> Number of eigenvalues and eigenvectors sought 20
> Number of Arnoldi vectors 40
>
> Convergence achieved after 61 iterations
>
> - Thermochemistry -
>
> Temperature: 298.150
> Pressure: 1.000
> Mass: 9195.156
>
> Principal moments of inertia in amu-A**2:
> 306533.05 2908243.03 2916073.81
>
> Vibrational frequencies in cm**-1
>
> 1 0.00001
> 2 0.00003
> 3 0.00003
> 4 0.00049
> 5 0.00052
> 6 0.00160
> 7 1.09146
> 8 1.28574
>
> I used the following NAB script
>
>
> mm_options("rgbmax=100., cut=999.0, ntpr=50, nsnb=99999, gb=1, diel=C,
> dielc=4");
Don't do this! The "dielc" parameter should not be used in conjunction with
gb. (The manual just says this parameter is for "non-gb" calcualations; I'll
update it to add a warning about not using it with gb.) You are effectively
screening charge-charge interactions twice.
>
> // get the normal modes:
> ier = nmode( m_xyz, 3*m.natoms,mme2, 500,2,0.0,0.0,0);
You should not set ntrun=2 here. It is computing the lowest two non-zero
frequencies, then quitting. Thermodynamics can only be computed if all the
eigenvalues are determined, so use ntrun=0 or 1.
....dac
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Received on Wed Jun 22 2011 - 05:30:04 PDT
