Nuclear quadrupole interaction Hamiltonian.

Hnq = ham_nq(Sys)
Hnq = ham_nq(Sys,nucSpins)
Hnq = ham_nq(Sys,nucSpins,'sparse')

ham_nq calculates the Hamiltonian of nuclear quadrupole interactions (NQI) in the spin system SpinSystem and returns it in Hnq. If only one argument is given, the NQI of all nuclei of the system are added. If the vector Nuclei is given, only nuclei specified in the vector are included in the calculation. In Nuclei, 1 determines the first nucleus, 2 the second and so on.

See the section about spin system structures on how to specify NQI parameters. See the section on and nuclear quadrupole interaction for more details about the Hamiltonian.

If 'sparse' is given as third argument, the Hamiltonian matrix is returned in sparse format instead of full format.

For a system AB with one electron and three nuclei, ham_nq(AB,2) returns the NQI Hamiltonian of the second nucleus only, whereas ham_nq(AB) gives the sum of the NQI of all three nuclei.

ham, ham_cf, ham_ee, ham_ez, ham_ezho, ham_hf, ham_nn, ham_nz, ham_oz, ham_so, ham_zf