CV:DIH

Navigation: Documentation / Collective Variables / CV:DIH

---

Distance

DD, DIS, MDIS, MDISG, ODIS, OPOS, OPOS2, ORAD, ORAD2, POS, RAD

Angle

ANG, ANG2, AXANG, AXANG2, DIH, DIH2, PANG, PVANG

Coordination

CNFF, CNGFF, CNSW, CNGSW, CNRF, CNGRF

Shape

ACYL, ASPH, EVEC, PMGTD, PMOGT, PLANE, RGYR, RMSDT, SANIS

Nucleic Acids

NALBPP, NASBPP, NASBPPOLD, NALSTP, NASSTP, NASSTPOLD, NASBO, NAPBO, NABEND

Puckering

PUCK6Q, PUCK6P, PUCK6T, PUCK5Q, PUCK5P

Special

WORMPOS, WORMANG

Energy

POT, EGAP

Algebra

ADD, SUB, MULT, DIV, FSWITCH, RSWITCH

Definition

The dihedral angle among four points. Each point is calculated as the center of mass of groups of atoms.

$\xi =sign({\mathbf{𝐧}}_2.({\mathbf{𝐀}}_{com}-{\mathbf{𝐁}}_{com}))*arccos\left(\frac{{\mathbf{𝐧}}_1.{\mathbf{𝐧}}_2}{|{\mathbf{𝐧}}_1|.|{\mathbf{𝐧}}_2|}\right)$

where normal vectors are defined as

${\mathbf{𝐧}}_1=({\mathbf{𝐀}}_{com}-{\mathbf{𝐁}}_{com})\times ({\mathbf{𝐂}}_{com}-{\mathbf{𝐁}}_{com})$ ${\mathbf{𝐧}}_2=({\mathbf{𝐂}}_{com}-{\mathbf{𝐁}}_{com})\times ({\mathbf{𝐂}}_{com}-{\mathbf{𝐃}}_{com})$

PBC note: The minimum-image convention is apllied to vectors |AB|, |CB|, and |CD| only if the fenable_pbc option is activated. The convention is not used to calculate the center of mass. It is therefore required that atoms within a group are either covalently bound or are part of complex that will not be separated or reimaged during a simulation.

Specification

Section name: DIH

Key	Type	Default	Description
name	string		unique CV name
group_a	mask		atoms specifying the point A
group_b	mask		atoms specifying the point B
group_c	mask		atoms specifying the point C
group_d	mask		atoms specifying the point D

Keys in bold are mandatory.