Reduced Serially Improved GTOs for Molecular Applications from H to Ar: Efficient Diffuse Functions in Augmented Basis Sets

A new family of Serially
Improved Gaussian-type Orbitals for Molecular
Applications (SIGMA) has been developed for hydrogen to argon and
is available in both standard and augmented versions. This new basis
set features a reduced number of primitive functions compared to the
original SIGMA set and eliminates the constraint of shared exponents
across different angular momentum shells. Its composition is similar
to that of the Dunning correlation-consistent basis sets. In the augmented
version of this novel SIGMA family, termed reduced SIGMA, the diffuse
primitive functions are contracted with others bearing higher exponents,
unlike in the corresponding Dunning sets, where they are added to
the set without contraction. This feature makes the reduced SIGMA
basis sets less susceptible to linear dependencies in large and compact
systems, which is reflected in better convergence of the minimization
process and has a positive impact on energy optimization procedures.
The improved performance of the augmented reduced SIGMA basis sets
over Dunning and other commonly used basis sets is demonstrated through
atomic and molecular calculations at various computational levels
across a broad set of systems.