| This is part of the colvar module |
Calculate the GHBFIX interaction energy among GROUPA and GROUPB using a potential defined in Kührová et al., Improving the performance of the AMBER RNA force field by tuning the hydrogen-bonding interactions, JCTC, 2019. Essentially it is a switching function being -1 for small distances and 0 for large distances with a smooth interpolation in the middle. This can be scaled as desired by specifying interaction scaling parameters and energy units.
This collective variable can be used to analyze hydrogen bond interactions, or to generate bias potentials. Notice that the value of the GHBFIX is returned in plumed units (see UNITS), if not specified differently via ENERGY_UNITS.
- Examples
- This example prints the GHBFIX interaction in kcal/mol between two groups of atoms using D_0, D_MAX and C It is applied in the functional form introduced in the pioneering paper. The types of atoms 1-6 should be defined in typesTable_examples.dat while their interaction parameters should be defined in scalingParameters_examples.dat in kBT units.
Click on the labels of the actions for more information on what each action computes
#SETTINGS AUXFOLDER=regtest/basic/rt-ghbfix
gh: GHBFIX =1,2,3 =4,5,6 =0.2 =0.3 =0.8 =typesTable_examples.dat =scalingParameters_examples.dat =kcal/mol You cannot view the components that are calculated by each action for this input file. Sorry
PRINT =output =gh You cannot view the components that are calculated by each action for this input file. Sorry
- Glossary of keywords and components
- Description of components
By default the value of the calculated quantity can be referenced elsewhere in the input file by using the label of the action. Alternatively this Action can be used to calculate the following quantities by employing the keywords listed below. These quantities can be referenced elsewhere in the input by using this Action's label followed by a dot and the name of the quantity required from the list below.
Quantity | Description |
.#!value | the GHBFIX interaction energy between the atoms in GROUPA and GROUPB |
- The atoms involved can be specified using
GROUPA | First list of atoms. For more information on how to specify lists of atoms see Groups and Virtual Atoms |
GROUPB | Second list of atoms (if empty, N*(N-1)/2 pairs in GROUPA are counted). For more information on how to specify lists of atoms see Groups and Virtual Atoms |
- Compulsory keywords
TYPES | the value of TYPES in the switching function |
PARAMS | the value of PARAMS in the switching function |
D_MAX | the value of D_MAX in the switching function |
D_0 | the value of D_0 in the switching function |
C | the value of C in the switching function |
- Options
NUMERICAL_DERIVATIVES | ( default=off ) calculate the derivatives for these quantities numerically |
NOPBC | ( default=off ) ignore the periodic boundary conditions when calculating distances |
SERIAL | ( default=off ) Perform the calculation in serial - for debug purpose |
PAIR | ( default=off ) Pair only 1st element of the 1st group with 1st element in the second, etc |
NLIST | ( default=off ) Use a neighbor list to speed up the calculation
|
NL_CUTOFF | The cutoff for the neighbor list |
NL_STRIDE | The frequency with which we are updating the atoms in the neighbor list |
ENERGY_UNITS | the value of ENERGY_UNITS in the switching function |