Theoretical investigation of the resonant hyper-Raman scattering by optical phonons

Two-phonon resonant hyper-Raman scattering treatment in a CdS crystal

“…It is known that the matrix element between s-and pexciton states is weakly dependent on the phonon wave vector, q, for qa 1 whereas J 0 (qa, κ S , n) ∝ q [16][17] However, it should be noted that the HRS induced by two-photon transition to a s-exciton is involved in a scattering process if the selection rules allow [20]. Our estimations performed for the one-phonon HRS have shown that its contribution to the hyper-Raman intensity can be appreciable in resonant conditions [20].…”

“…Our estimations performed for the one-phonon HRS have shown that its contribution to the hyper-Raman intensity can be appreciable in resonant conditions [20]. Because of this, we consider the 2LO-scattering mechanism caused by twophoton transition to a s-exciton too.…”

“…,q is the unit vector in the direction of q. Hereafter the designation is used: Θ ξ = n for ξ = n or Θ ξ = i/k for ξ = k. Because the frequency of incident radiation is away from the resonance, J 4 (n, κ L ) can be approximated by [20]. We note that J l (Q, κ S , n) was obtained by us in [16] and is defined by the expression (27).…”

The analysis of the two‐phonon resonant hyper‐Raman effect

“…Because the RHRS is considered for the doubled energy of exciting radiation below the 2P exciton level, the Green's function approach used in the theory of two-photon absorption [6,7] can be applied in calculations of the sums over 4 λ and 2 λ . The corresponding relations were derived by us earlier [4,8]. …”

Theoretical treatment of the first-order hyper-Raman scattering in semiconductors

“…A scattering process was considered by authors in the framework of two-band model. Theoretical investigation of the HRS under two-photon excitation near the energy gap was performed by us 16 . We took into account transitions in higher-lying conduction bands and from deeper valence bands and considered different mechanisms of exciton-photon and exciton-lattice interactions.…”