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============ determinants ============ Contains everything for the computation of the Hamiltonian matrix elements in the basis of orthogonal Slater determinants built on a restricted spin-orbitals basis. The main providers for this module are: * :option:`determinants n_states`: number of states to be computed * :c:data:`psi_det`: list of determinants in the wave function used in many routines/providers of the |QP|. * :c:data:`psi_coef`: list of coefficients, for all :option:`determinants n_states` states, and all determinants. The main routines for this module are: * :c:func:`i_H_j`: computes the Hamiltonian matrix element between two arbitrary Slater determinants. * :c:func:`i_H_j_s2`: computes the Hamiltonian and (|S^2|) matrix element between two arbitrary Slater determinants. * :c:func:`i_H_j_verbose`: returns the decomposition in terms of one- and two-body components of the Hamiltonian matrix elements between two arbitrary Slater determinants. Also return the fermionic phase factor. * :c:func:`i_H_psi`: computes the Hamiltonian matrix element between an arbitrary Slater determinant and a wave function composed of a sum of arbitrary Slater determinants. For an example of how to use these routines and providers, take a look at :file:`example.irp.f`.