For orbitals of angular momentum l > 0, standard quantum chem software takes the contraction for a given orbital and creates 2l+1 identical copies. For example, for p- or d-orbitals, it creates 3 and 5 copies of a given p- and d-contraction specified in the basis set input, corresponding to the different spherical harmonics (px, py, pz, or dxz, dxy, dyz, dz2, dx2-y2). Each of these copies has the same set of contraction coefficients, e.g. the contraction coefficients for px are the same as for py and pz.
Would it be possible to use or modify Psi4 (and if so, how?) to do the following:
Specify a different contraction for every spherical harmonic, i.e. different coefficients for px than for py and pz (but same basis functions i.e. same exponents). Then, when running the calculation (say, a Hartree-Fock calculation), the program should not triplicate the contraction for a p-orbital, but instead, build molecular orbitals with each contraction (px, py, pz) appearing only once in the linear combination of atomic orbitals.