Correcting Basis Set Incompleteness in Wave FunctionCorrelation Energy by Dressing Electronic Hamiltonian with an EffectiveShort-Range Interaction

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We propose a generalapproach to reducing basis set incompletenesserror in electron correlation energy calculations. The correctionis computed alongside the correlation energy in a single calculationby modifying the electron interaction operator with an effective short-rangeelectron–electron interaction. Our approach is based on a localmapping between the Coulomb operator projected onto a finite basisand a long-range interaction represented by the error function witha local range-separated parameter, originally introduced by Gineret al. [J. Chem. Phys.2018, 149, 19430130466264]. Unlike the basis set incompleteness error correction proposedin that work, our method does not rely on short-range correlationdensity functionals. As a numerical demonstration, we apply the methodwith complete active space wave functions. Correlation energies arecomputed using two distinct approaches: the linearized adiabatic connection(AC0) method and n-electron valence state second-orderperturbation theory (NEVPT2). We obtain encouraging results for therelative energies of test molecules, with accuracy in a triple-ζbasis set comparable to or exceeding that of uncorrected AC0 or NEVPT2energies in a quintuple-ζ basis set.