Note

This website is presently under development. The primary website for MOPAC is still http://openmopac.net until the majority of its contents have been migrated here.

SNAP

Snap a bond or torsion angle in a Z-matrix geometry to the nearest value of the form \(\arccos(\sqrt{a/b}) + 180 c\) degrees for integers \(a\), \(b\), and \(c\) if they match to within approximately 2 to 3 decimal places. Angles of this form are common in high-symmetry geometries, and SNAP is a convenience that avoids having to type all of the significant figures of an irrational number to double precision.

Snapped angles are printed in the output file, and users should check that enough precision was provided for the desired snapping to occur.

Auto-detection is limited to \(|a| \le 7\).