9.4.1 Introduction

DISTORT
       Specifies whether to apply pressure or external force to a chemical system
TYPE:
       LOGICAL
DEFAULT:
       False
OPTIONS:
       False Do not use pressure or force True Use pressure or force
RECOMMENDATION:
       Set to true to apply pressure or force.

Model
       Specifies which model is used to distort the molecule.
INPUT SECTION: $distort
TYPE:
       STRING
DEFAULT:
       None
OPTIONS:
       HCFF Hydrostatic Compression Force Field¹⁰⁶⁷ XHCFF eXtended Hydrostatic Compression Force Field¹⁰⁶⁹ GOSTSHYP Gaussians On Surface Tesserae Simulate HYdrostatic Pressure⁹⁹⁷ EFEI External Force is Explicitly Included (Section 9.5)
RECOMMENDATION:
       Please refer to the following subsections for recommendations on which model to use.

Pressure
       Specifies the pressure (in MPa) used to compress the molecule.
INPUT SECTION: $distort
TYPE:
       DOUBLE
DEFAULT:
       None
OPTIONS:
       User defined
RECOMMENDATION:
       None

NPoints_Heavy
       Specifies the number of tessellation points per non-hydrogen atom.
INPUT SECTION: $distort
TYPE:
       INTEGER
DEFAULT:
       110
OPTIONS:
       User defined
RECOMMENDATION:
       Use the default.

NPoints_Hydrogen
       Specifies the number of tessellation points per hydrogen atom.
INPUT SECTION: $distort
TYPE:
       INTEGER
DEFAULT:
       110
OPTIONS:
       User defined
RECOMMENDATION:
       Use the default.

Scaling
       Specifies the scaling factor of the atomic van der Waals radii used in the tessellation of the molecular surface, which is used in the pressure models.
INPUT SECTION: $distort
TYPE:
       DOUBLE
DEFAULT:
       1.2
OPTIONS:
       User defined
RECOMMENDATION:
       Increase when modeling a chemical complex to make sure that the complex is placed inside a single cavity.⁹⁹⁷ A value of 1.0 was suggested to be used in the X-HCFF model.¹⁰⁶⁹

Gostshyp_Mem
       Specifies the amount of memory, the gostshyp model is allowed to allocate in MB.
INPUT SECTION: $distort
TYPE:
       INTEGER
DEFAULT:
       $66\%$ of MEM_TOTAL
OPTIONS:
       User defined
RECOMMENDATION:
       Set larger than expected gostshyp memory usage. As a rule of thumb gostshyp will need $5\cdot N_{Basis}^2\cdot N_{tess}$ Bytes memory.

screener
       Enables/disables Integral screening for gostshyp calculations.
INPUT SECTION: $distort
TYPE:
       BOOL
DEFAULT:
       true
OPTIONS:
       true Enable integral screening for gostshyp false Disable integral screening for gostshyp
RECOMMENDATION:
       Use default. Disabling integral screening will lead to much higher memory usage and severe performance drops.