Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Primer on Atomic Orbital Basis Sets

To introduce the concepts of a basis set and basis functions, we begin with a simple (unknown) function of a single variable, f x). A variety of procedures can be used to fit (or estimate) this function. For example, a simple power series could be used to approximate this simple function of the variable x  [Pg.64]

Here we are using a basis set to approximate the unknown function f x). The basis functions are od i = 0,1,2,3. The expansion coefficients, c are determined by some sort of procedure that adjusts their values in order to obtain the best fit to the function f x). The approximation can generally be improved by using a larger basis set. [Pg.65]

Because of the systematic nature of the correlation-consistent family of basis sets, it is possible to use extrapolation techniques to estimate the CBS limit. For example, the three-parameter exponential function introduced by Feller nicely describes the convergence of SCF energy to the CBS limit with [Pg.66]

For the fitting of correlation energies obtained with extremely large hextuple-and heptuple-zeta (6Z and 7Z) basis sets, the following revision to Eq. [43] has been suggested based on MP2 pair energies  [Pg.67]

Martin has proposed a two-parameter fit to a quartic polynomial (Schwartz4) and a three-parameter fit to a sixth-degree polynomial (Schwartz6)  [Pg.67]


See other pages where Primer on Atomic Orbital Basis Sets is mentioned: [Pg.64]   


SEARCH



Atomic basis

Atomic orbital basis sets

Atomic orbitals basis sets

Basis atomic orbital

Basis orbitals

Basis set orbitals

Basis set, atomic

Orbital basis set

© 2024 chempedia.info