Question

Reading through a handout from Yale shows the author correlating the ECP with Pople basis sets. The author of this says the corresponding basis set for SDD is 6-31G, Def2TZV as 6-311G, LANL2MB as STO-3G, etc... I'm confused between the correlation between the two, as I thought they were entirely different sets of LCAO's that can't be directly correlated. Are a portion of one of these ECP's constructed with Pople basis sets? Or am I misunderstanding?

Direction (link to a publication, article, etc) would be greatly appreciated so I can clarify my misunderstanding and learn about this, and clear any gaps in knowledge. Thank you.

Answer 1

The ECP and basis sets are used together in computational chemistry calculations to accurately describe the behavior of electrons in a molecule.

Step-by-step explanation:

The ECP (Effective Core Potential) method is commonly used in computational chemistry to reduce the computational cost of quantum mechanical calculations. In this method, the core electrons are replaced with a pseudopotential, allowing for a more efficient calculation.

However, the valence electrons are still described using basis sets, such as Pople basis sets or other commonly used basis sets like 6-31G and STO-3G. The basis sets provide a set of functions that can accurately describe the behavior of the valence electrons.

So, while the ECP and basis sets are different aspects of the calculation, they are both used together to accurately describe the behavior of the electrons in a molecule.