Solvent tab
The Solvent tab allows you to configure a simulated solvent environment for the calculation.
Solvent: Select a solvent to use as the solvent environment for the calculation. Available options are:
- Acetone
- Acetonitrile
- Benzene
- Carbon tetrachloride
- Chlorobenzene
- Chloroform
- Cyclohexane
- Diethyl ether
- Dimethyl sulfoxide
- Ethanol
- Methanol
- Methylene chloride
- n-hexane
- n-hexadecane
- Nitrobenzene
- Pyridine
- Water
When you select a solvent, the Dielectric constant field automatically updates with the appropriate value.
If you specify the Dielectric constant parameter to a value different from that dictated by the selected solvent, the Solvent displays as Customized.
Dielectric constant: Specify a value for the solvent dielectric constant. This parameter automatically updates to the appropriate value when you select a solvent from the Solvent dropdown list. However, you can enter your own custom value if you want.
Include apolar term: Request calculation of apolar (non-electrostatic) contributions to the solvation energy. These contributions arise from cavitation and solute-solvent dispersion-repulsion. Calculations without the apolar term cannot reliably estimate solvation energies, especially for neutral molecules, and particularly so if these molecules are large.
The Solvent surface tension and Account for solute-solvent dispersion repulsion controls are enabled only when you select the Include apolar term checkbox.
Solvent surface tension: The surface tension of the solvent (in N/m) for evaluation of the apolar term.
Account for solute-solvent dispersion repulsion: The CASTEP solvation model suggests scaling of the surface tension that enters the expression for the apolar term, to account for the solute-solvent dispersion-repulsion. The default dimensionless scaling factor is 0.281075 (see Dziedzic, 2011).
Use at least a Fine FFT grid Density for solvation calculations; the Precise density is even better. You can specify the FFT grid Density on the
Basis tab of the CASTEP Electronic Options dialog. Also use an increased value of Augmentation density scaling factor, for example 1.5-2.0 instead of the default value of 1.0.
An increased FFT density and energy cutoff can help to eliminate convergence errors for the multigrid solver for electrostatics in a solvent.
Access methods
| Menu | Modules | CASTEP | Calculation | Electronic | More... | Solvent |
| Toolbar |
 | Calculation | Electronic | More... | Solvent
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See Also:
Self-consistent electronic minimization
Setting electronic options
Electronic tab - CASTEP Calculation dialog
Basis tab - CASTEP Electronic Options dialog
SCF tab - CASTEP Electronic Options dialog
k-points tab - CASTEP Electronic Options dialog
Potentials tab - CASTEP Electronic Options dialog
CASTEP Density Mixing Options dialog
CASTEP Occupancy Options dialog
Self-consistent electronic minimization