Contents: Table of Contents   Chapter 4  Chapter 4

Introduction

One of the most important features of any ab initio program is the ability to find optimised geometries of minima and saddle points. Doing this efficiently depends upon analytic energy gradients. This chapter describes the operation of the geometry optimisers.

The sections in this chapter are

Calculating one energy gradient

Finding minima

Constants, variables and partial optimisations

Detailed control of optimisations

Alternative algorithms

PRINT and PUNCH controls

Using force constants in a Geometry Optimisation

Finding transition states

Restarting incomplete optimisations

The keywords covered in this chapter are

	GRADIENT	OPTIMISE	VARIABLES	CONSTANTS	GRADTOL
	NUMGRAD	MAXSTEP	EMAX	CARTESIAN	FCM
	EIGMIN	BFGS	AUGHES	GDIIS	SADDLE

and some PRINT and PUNCH directives.
 

    
Contents: Table of Contents   Chapter 4  Chapter 4