towhee-users Mailing List for MCCCS Towhee

Dear all,
 I just try to run the examples in the towhee, but there is an fatal error :

Mismatch of strings in readclassical
   Expected String: classical_potential
   Found String:
what does this mean?
where can I find the readclassical?
how to solve it?

Boran Zhou

Dept of Mechanical Engineering
University of South Carolina

Dear all,
I am new to towhee, I just learned how to use the grand canonical monte
carlo method to simulate the adsorption of water molecule on the surface of
the nanowire, I just read the towhee manual and do not know how to run the
examples, let alone code written by myself?
Is it like in lammps  ./lmp_serial> input
thanks

peter

Hello,

I’ve been using Towhee for a little over 6 months now and have found
it very useful for methane (single-site model) and oxygen (3-site
model) adsorption.

However, I’ve tried to implement a 5-site rigid model of methane, and
receive the error:

GETCBANGLE: all choices have infinite energy
 for the angle B selection
 molecule type:           1
 iufrom,iuprev,ntogrow:           1           4           3


I’m using the current version of Towhee.  I have tried increasing and
decreasing the bond angle tolerance value in the forcefield file, but
still receive the error.  I suspect that the problem has to do with
defining all of the H-C-H angles properly, or that all angles cannot
be kept within the tolerance.  I have defined the C-H bondlength and
H-C-H angle in the forcefield file.  Is the problem that while growing
the molecule, there are no further “options” to place an H atom that
allows all H-C-H angles to remain within the given tolerance?

Here are my angle coefficients from my forcefield file:
Angle Style
           0
Angle Coefficients
    0.1094710000E+03
    0.5000000000E-03

I am using:
cbmc_formulation
'Martin and Frischknecht 2006'
cbmc_setting_style
'default ideal'

In my input file, I have:

input_style
'basic connectivity map'
nunit
  5
nmaxcbmc
  5
lpdbnames
  F
forcefield
'air'
charge_assignment
'bond increment'
unit ntype
1    'C_CH4'
vibration
  4
  2 3 4 5
improper torsion
  0
unit ntype
2    'H_CH4'
vibration
  1
  1
improper torsion
  0
unit ntype
3    'H_CH4'
vibration
  1
  1
improper torsion
  0
unit ntype
4    'H_CH4'
vibration
  1
  1
improper torsion
  0
unit ntype
5    'H_CH4'
vibration
  1
  1
improper torsion
  0

I can post other relevant pieces of my forcefield file or input file
if that would be helpful.

Is there something I am missing as far as being able to setup a rigid
“3-D” molecule in Towhee?  The oxygen molecule was easier to set up
since it involved only one 180 degree angle.  Also, I have
successfully run GCMC simulations with a rigid methane molecule (all
angles stayed at exactly 109.471 degrees) using Materials Studio (also
using configurational bias).

Thank you for your help,

Todd