FIXED_ATOMS

Section can be repeated.

This section is used to constraint the fractional atomic position (X,Y,Z). Note that fractional coordinates are constrained, not real space coordinates. In case a restraint is specified the value of the TARGET is considered to be the value of the coordinates at the beginning of the run or alternatively the corresponding value in the section: FIX_ATOM_RESTART. [Edit on GitHub]

Subsections

Keywords

Keyword descriptions

COMPONENTS_TO_FIX

Type: enum
Default: XYZ
Usage: COMPONENTS_TO_FIX (x|y|z|xy|xz|yz|xyz)

Description: Specify which fractional components (X,Y,Z or combinations) of the atoms specified in the section will be constrained/restrained.

Valid values:

  • X Fix only X component

  • Y Fix only Y component

  • Z Fix only Z component

  • XY Fix X-Y components

  • XZ Fix X-Z components

  • YZ Fix Y-Z components

  • XYZ Fix the full components of the atomic position.

Mentions: ⭐Geometry and cell optimization

[Edit on GitHub]

EXCLUDE_MM

Type: logical
Default: F
Lone keyword: T
Usage: EXCLUDE_MM

Description: Does not apply the constraint to the MM region within a QM/MM calculation. This keyword is active only together with MOLNAME

[Edit on GitHub]

EXCLUDE_QM

Type: logical
Default: F
Lone keyword: T
Usage: EXCLUDE_QM

Description: Does not apply the constraint to the QM region within a QM/MM calculation. This keyword is active only together with MOLNAME

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LIST

Type: integer[ ]
Repeatable: yes
Usage: LIST {integer} {integer} .. {integer}

Description: Specifies a list of atoms to freeze.

Mentions: ⭐Geometry and cell optimization

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MM_SUBSYS

Type: enum
Default: NONE
Aliases: PROTEIN
Usage: MM_SUBSYS (NONE|ATOMIC|MOLECULAR)

Description: In a QM/MM run all MM atoms are fixed according to the argument.

Valid values:

  • NONE fix nothing

  • ATOMIC only the MM atoms itself

  • MOLECULAR the full molecule/residue that contains a MM atom (i.e. some QM atoms might be fixed as well)

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MOLNAME

Type: string[ ]
Repeatable: yes
Aliases: SEGNAME
Usage: MOLNAME WAT MEOH

Description: Specifies the name of the molecule to fix

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QM_SUBSYS

Type: enum
Default: NONE
Usage: QM_SUBSYS (NONE|ATOMIC|MOLECULAR)

Description: In a QM/MM run all QM atoms are fixed according to the argument.

Valid values:

  • NONE fix nothing

  • ATOMIC only the QM atoms itself

  • MOLECULAR the full molecule/residue that contains a QM atom (i.e. some MM atoms might be fixed as well)

[Edit on GitHub]