Gaussian Approximations to 1s Slater-Type Orbitals
Snapshot 1: STO-1G orbital, best fit with =0.27
Snapshot 2: RDF for STO-2G, best fit around =0.14, =0.70
Snapshot 3: RDF for STO-3G, best fit around =0.15, =0.50, =2.0
For more information:
S. M. Blinder, Introduction to Quantum Mechanics in Chemistry, Materials Science, and Biology, Burlington, MA: Elsevier Academic Press, 2004 pp. 187–188.