Extrapolation to the complete basis set limit of structural parameters: comparison of different approaches.

For the first time, different procedures for extrapolating structural parameters to the complete basis set limit are compared. More precisely, a well-tested scheme, based on extrapolated gradients, is employed for validating the extrapolation procedure directly applied to geometrical parameters by means of different extrapolation functions. For this purpose, a set of small systems (mostly triatomics), also containing second-row elements, has been chosen.