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update documentation

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Shern Ren Tee 2022-11-22 14:56:55 +10:00 committed by Shern Tee
parent e58b71b0c9
commit 9958c9dfd7
1 changed files with 16 additions and 10 deletions
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26
doc/src/fix_electrode_conp.rst
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@ -139,17 +139,22 @@ For both *cg* methods, the command must specify the conjugate gradient
tolerance. *fix electrode/thermo* currently only supports the *mat_inv*
algorithm.
For *fix electrode/conp*, the keyword *symm* can be set *on* (or *off*) to turn
on (or turn off) the constraint requiring total electrode charge to be zero.
With *symm off*, the potentials specified are absolute potentials, but the
charge configurations satisfying them may add up to an overall non-zero, varying
The keyword *symm* can be set *on* (or *off*) to turn on (or turn off)
the capacitance matrix constraint that sets total electrode charge to be zero.
This has slightly different effects for each *fix electrode* variant.
For *fix electrode/conp*, with *symm off*, the potentials specified are absolute potentials,
but the charge configurations satisfying them may add up to an overall non-zero, varying
charge for the electrodes (and thus the simulation box). With *symm on*, the
total charge over all electrode groups is constrained to zero.
total charge over all electrode groups is constrained to zero, and
potential differences rather than absolute potentials are the physically relevant quantities.
The *symm* keyword is not allowed for *electrode/conq*, for which overall
neutrality is explicitly obeyed or violated by the user input, and for
*electrode/thermo*, for which overall neutrality is always automatically
imposed.
For *fix electrode/conq*, with *symm off*, overall neutrality is explicitly obeyed or
violated by the user input (which is not checked!). With *symm on*, overall neutrality
is ensured by ignoring the user-input charge for the last listed electrode (instead,
its charge will always be minus the total sum of all other electrode charges). For
*fix electrode/thermo*, overall neutrality is always automatically imposed for any setting
of *symm*, but *symm on* allows finite-field mode (*ffield on*, described below)
for faster simulations.
For all three fixes, any potential (or charge for *conq*) can be specified as an
equal-style variable prefixed with "v\_". For example, the following code will
@ -213,7 +218,8 @@ by cell length. The internal commands use variable so that the electric field
will correctly vary with changing potentials in the correct way (for example
with equal-style potential difference or with *fix electrode/conq*). This
keyword requires two electrodes and will issue an error with any other number of
electrodes.
electrodes. This keyword requires electroneutrality to be imposed (*symm on*)
and will issue an error otherwise.
For all versions of the fix, the keyword-value *etypes on* enables type-based
optimized neighbor lists. With this feature enabled, LAMMPS provides the fix