K. Ruud et al., A NUMERICALLY STABLE ORBITAL CONNECTION FOR THE CALCULATION OF ANALYTICAL HESSIANS USING PERTURBATION-DEPENDENT BASIS-SETS, Chemical physics letters, 235(1-2), 1995, pp. 47-52
It is demonstrated that calculations of second-order molecular propert
ies using perturbation-dependent basis sets are most efficiently carri
ed out using the natural connection.