potentialsinternal

Potentialsinternal is a term used in theoretical and computational contexts to denote the internal component of a system’s potential energy, distinct from external potentials imposed by fields, boundaries, or environments. The precise meaning varies by discipline and software, and some sources simply refer to it as intramolecular or internal potential energy.

In a typical energy decomposition, the total potential energy V(r) is written as a sum of an external part and an internal part: V(r) = V_ext(r) + V_int(r). The internal potential captures interactions that arise from the system’s own structure and constituents. Common internal contributions in molecular and materials modeling include bond stretching, angle bending, and torsional (dihedral) rotations. Many force fields express these as bonded terms such as k_b (r − r0)^2 for bonds, k_theta (theta − theta0)^2 for angles, and V_dihedral(phi) often represented by a periodic function V_n/2 [1 + cos(n phi − gamma)]. Improper terms may be used to enforce planarity or chirality. Depending on the model, certain nonbonded interactions within a molecule (such as 1-4 interactions) may be included in or excluded from V_int.

Applications of the internal potential are widespread in molecular mechanics, molecular dynamics, quantum chemistry, and materials modeling. Analyzing V_int helps researchers understand how internal rearrangements, conformational changes, and vibrational modes influence a system’s energy landscape, stability, and properties.

Notes and caveats: the label poten tialsinternal is not universally standardized; different software packages and theoretical frameworks may partition energy differently or use alternative terminology. Users should consult specific documentation to understand how internal potentials are defined and separated from external contributions. See also: potential energy, internal coordinates, force field, potential energy surface.