# CFOUR_GEO_METHOD

> Specifies the used geometry optimization methods. The following values are permitted: NR (=0) — straightforward Newton-Raphson search for minimum; RFA (=1) — Rational Function Approximation search for minimum (this method can be used to find minima when the initial structure is in a region where the Hessian index is nonzero); TS (=2) Cerjan-Miller eigenvector following search for a transition state (can be started in a region where the Hessian index is not equal to unity); MANR (=3) — Morse-adjusted Newton-Raphson search for minimum (very efficient minimization scheme, particularly if the Hessian is available); SINGLE_POINT (=5) for a single-point energy calculation. ENERONLY (=6) requests a geometry optimization based on single-point energy calculations. Default: SINGLE-POINT (NR as soon as variables are marked to be optimized).

> - Type: string
> - Possible Values: NR, RFA, TS, MANR, SINGLE_POINT, ENERONLY
> - Default: SINGLE_POINT