Third-order electron-correlation and crystal-field contributions to the amplitudes of two-photon absorption infNsystems

Sum rules for multi-photon spectroscopy of ions in finite symmetry

“…To close this Letter, some remarks are in order. In the particular case p = 1 and 2, the Hamiltonian model given by (20) and (21) unifies various models described in the literature for rare earth ions and transition-metal ions. The originality of this work rests on the use of symmetry adaptation methods for the chain SU (2) ⊃ G * in conjunction with a very general Hamiltonian model for describing simultaneous absorption of p photons between Stark levels (rather than between J levels).…”

Symmetry adaptation techniques in n-photon absorption spectroscopy

“…We know that for intra-configurational two-photon transitions, some additional mechanisms (additional with respect to the second-order mechanisms arising from secondorder time-dependent perturbation theory) have been introduced by various authors [6,7,9,11] in order to produce more efficient third-and fourth-order mechanisms. For instance, the third-order mechanisms introduced by Judd and Pooler [6] arise from secondorder time-dependent perturbation theory plus first-order time-independent perturbation theory.…”

“…The basic corresponding theoretical models have been developed by Judd [1] and Ofelt [2] for intra-configurational onephoton transitions (see [20] for a recent review) and by Axe [3] for intra-configurational two-photon transitions. The case of two-photon transitions has been the object of further works and extensions : (i) introduction of higher-order mechanisms for intraconfigurational transitions [6,7,9,11], (ii) development of models for inter-configurational transitions [10,12,15,21], and (iii) introduction of symmetry considerations from both a qualitative [4,5] and a quantitative [13,14,18,19,21,22] viewpoint.…”

Polarization dependence of two-photon absorption and electronic Raman scattering intensitiesin crystals

“…For transitions between non-Kramers state, the TPA contributions from a singlet ͑⌿ i ͒ to each state of a doubly degenerate level ͑⌿ f x or ⌿ f y ͒ are equal, 61 i.e., ͉␣ 21 …”

“…Sztucki and Strek, [16][17][18][19] expanding Reid and Richardson's idea, proposed the thirdorder contributions to the two-photon processes from the static and dynamic coupling mechanisms developed within the independent systems model. Smentek-Mielczarek et al [20][21][22][23][24] examined the third-order electron-correlation and crystal-field contributions to the two-photon amplitude within the framework of double perturbation theory. 25,26 All of the mechanisms mentioned above have been applied to intraconfigurational two-photon transitions, where the initial and final states both belong to the f N configurations and the two-photon processes are therefore allowed because of the parity rule.…”