bsse

BSSE, commonly written as BSSE, stands for Basis Set Superposition Error, a methodological issue in quantum chemistry. It occurs when the finite basis set used to describe a molecular system allows the basis functions of one fragment to artificially stabilize another fragment, leading to an overestimation of binding or interaction energies. This artifact is especially pronounced in calculations of weakly bound systems, such as van der Waals complexes or adsorption energies, and can distort reported energy differences.

To mitigate BSSE, several approaches are used. The counterpoise correction, introduced by Boys and Bernardi in 1970, estimates and subtracts the spurious stabilization by performing calculations with ghost orbitals. Other strategies include using larger or more complete basis sets and applying complete basis set extrapolation. In practice, BSSE is routinely considered in high-accuracy computational studies and in benchmarking new methods.

In other contexts, BSSE may be an acronym for organizations, programs, or societies unrelated to chemistry. Because the meaning depends on context, readers should consult accompanying text to determine the intended expansion of the acronym.