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Subsections

## Angles

### angle: angle between three groups.

The angle {...} block defines an angle, and contains the three blocks group1, group2 and group3, defining the three groups. It returns an angle (in degrees) within the interval .

• group1: see definition of group1 (distance component)
• group2: analogous to group1
• group3: analogous to group1
• forceNoPBC: see definition of forceNoPBC (distance component)
• oneSiteTotalForce: see definition of oneSiteTotalForce (distance component)

### dipoleAngle: angle between two groups and dipole of a third group.

The dipoleAngle {...} block defines an angle, and contains the three blocks group1, group2 and group3, defining the three groups, being group1 the group where dipole is calculated. It returns an angle (in degrees) within the interval .

• group1: see definition of group1 (distance component)
• group2: analogous to group1
• group3: analogous to group1
• forceNoPBC: see definition of forceNoPBC (distance component)
• oneSiteTotalForce: see definition of oneSiteTotalForce (distance component)

### dihedral: torsional angle between four groups.

The dihedral {...} block defines a torsional angle, and contains the blocks group1, group2, group3 and group4, defining the four groups. It returns an angle (in degrees) within the interval . The Colvars module calculates all the distances between two angles taking into account periodicity. For instance, reference values for restraints or range boundaries can be defined by using any real number of choice.

• group1: see definition of group1 (distance component)
• group2: analogous to group1
• group3: analogous to group1
• group4: analogous to group1
• forceNoPBC: see definition of forceNoPBC (distance component)
• oneSiteTotalForce: see definition of oneSiteTotalForce (distance component)

### polarTheta: polar angle in spherical coordinates.

The polarTheta {...} block defines the polar angle in spherical coordinates, for the center of mass of a group of atoms described by the block atoms. It returns an angle (in degrees) within the interval . To obtain spherical coordinates in a frame of reference tied to another group of atoms, use the fittingGroup () option within the atoms block. An example is provided in file examples/11_polar_angles.in of the Colvars public repository.

• atoms Atom group
Context: polarPhi
Acceptable values: atoms {...} block
Description: Defines the group of atoms for the COM of which the angle should be calculated.

### polarPhi: azimuthal angle in spherical coordinates.

The polarPhi {...} block defines the azimuthal angle in spherical coordinates, for the center of mass of a group of atoms described by the block atoms. It returns an angle (in degrees) within the interval . The Colvars module calculates all the distances between two angles taking into account periodicity. For instance, reference values for restraints or range boundaries can be defined by using any real number of choice. To obtain spherical coordinates in a frame of reference tied to another group of atoms, use the fittingGroup () option within the atoms block. An example is provided in file examples/11_polar_angles.in of the Colvars public repository.