Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Topics - Christopher

Pages: [1]
1
Input files and parameters / Miture Grand canonical MC Fugacity
« on: December 18, 2020, 06:51:24 PM »
Dear RASPA fellows,

I want to do a Simulation in the Grand canonical ensemble in a COF. So the thermodynamic state is already chosen and I want to specify a fugacity coefficient that I calculated with PC-SAFT EOS.

The coefficient is already calculated in a mixture let's say 0.8 Molfrac methane and 0.2 Molfrac butane.

How do i correctly put in all necessary things. I think need:
ExternalPressure
FugacityCoefficient
MolFraction
IdealGasRosenbluthweight (for butane while methane is 1.)

Why do I have to specify the molfrac? Is this input fine now?
Best Christopher

2
Input files and parameters / 1_2_ethanediol TraPPE modell
« on: July 05, 2020, 03:38:04 PM »
Dear Dr Dubbeldam,

I tried to do a GibbsEnsemble simulation of ethanediol with the TraPPE modell. First I had some problems reading in the IntraCoulomb interactions. In the Outputfile Raspa set a scaling value of e-314 for some of them. After setting some extra IntraVDW interactions that I just scaled to zero it now seems that raspa is reading them in properly. But the Simulation gets somehow stuck. There is no exchange between the boxes and also the gibbsvolumechangemove is not working anymore (is not accepted).  Here is my molecule.def file:

# critical constants: Temperature [T], Pressure [Pa], and Acentric factor [-]
0.0
0.0
0.0
# Number Of Atoms
6
# Number Of Groups
1
# Alkane-group
flexible
# number of atoms
6
# atomic positions
0 H_alc
1 O_alc
2 CH2_alc
3 CH2_alc
4 O_alc
5 H_alc
# Chiral centers Bond  BondDipoles Bend  UrayBradley InvBend  Torsion Imp. Torsion Bond/Bond Stretch/Bend Bend/Bend Stretch/Torsion Bend/Torsion IntraVDW IntraCoulomb
               0    7            0    4            0       0        3            0         0            0         0               0            0        6           6
# Bond stretch: atom n1-n2, type, parameters
0 1 FIXED_BOND 0.945
1 2 FIXED_BOND 1.43
2 3 FIXED_BOND 1.54
3 4 FIXED_BOND 1.43
4 5 FIXED_BOND 0.945
0 4 LJ_12_6_BOND 75000000 0
1 5 LJ_12_6_BOND 75000000 0
# Bond bending: atom n1-n2-n3, type, parameters
0 1 2 HARMONIC_BEND 55400 108.5
1 2 3 HARMONIC_BEND 50400 109.47
2 3 4 HARMONIC_BEND 50400 109.47
3 4 5 HARMONIC_BEND 55400 108.5
# Torsion n1-n2-n3-n4 type
0 1 2 3 TRAPPE_DIHEDRAL    0.0   209.82   -29.17    187.93
1 2 3 4 TRAPPE_DIHEDRAL  503.24    0.0   -251.62   1006.47
2 3 4 5 TRAPPE_DIHEDRAL    0.0   209.82   -29.17    187.93
# intra vdw
0 3
0 3
0 3
0 3
0 3
0 3
# intra C
0 3
0 4
0 5
1 4
1 5
2 5
# Number of config moves
0

I did exactly the same simulation for 1-5 pentanediol and everything is working fine (Same simulation.input, pseudo_atoms and forcefield files). This one does not have the LJ_12_6_BOND repulsive term. Can you point out anything that I missed?

Thanks in advance!
Best
Christopher

3
Input files and parameters / Gibbs Ensemble MC
« on: April 17, 2020, 09:57:43 AM »
Hello Dr. Dubbeldam,

I am doing NpT Gibbs Ensemble Simulations. Often the Simulations crash because of small boxes. I had the idea to restart the Simulation at that point (Crashrestart) but with additional molecules. Is this possible?

If yes what are the options for:
RestartFile
ContinueAfterCrash
CreateMolecules

Did I forget something else? Thanks in advance for your help!
Best Christopher Ke├čler

Pages: [1]