Simulations of vibronic profiles in two-photon absorption

Vibronic contributions to resonant NLO responses: two-photon absorption in push–pull chromophores

“…Among other properties, large two-photon absorption (TPA) cross-sections are promising for different applications, ranging from optical storage to biological optical imaging 1 . As a consequence, both experimental and theoretical work [2][3][4][5][6][7] have received strong impetus and several interesting strategies have been proposed to improve NLO responses in general 8,9 and TPA cross-section in particular 1,10 . A presently highly debated topic concerns the importance of vibrational contributions to NLO responses of organic materials [11][12][13][14] .…”

Vibration and two-photon absorption

“…This is not the first time that the vibrational effects in TPA have been investigated, but all previous attempts have been much less complete. In nearly all cases attention has zeroed in on the ͕␣ 2 ͖ TP term where vibrational averaging has been done exactly by Sundholm et al 27 or approximately by Å gren and co-workers [24][25][26] ͑either just the first or the first two terms in the expansion of Eq. ͑17͒ have been included͒.…”

“…The first theoretical treatment of vibronic coupling, based on the linear Herzberg-Teller term, was carried out by Honig and co-workers 21,22 for benzene. Ab initio calculations were later carried out by Luo and co-workers, 23,24 and the theory was extended to include the Franck-Condon distribution by Macak et al 25,26 Other related studies are by Sundholm et al, 27 where vibrationally averaged transition moments were employed for CO, and by Painelli et al 28 who used an approximate two-state model to account for electronic-vibrational coupling in push-pull chromophores. Here we present a more complete and more general approach to the vibrational problem.…”

Theoretical study of phosphorescence in dye doped light emitting diodes

“…36 The TD DFT QR calculations of the S-T transition moments in all porphyrins and their vibrational mode dependence are performed with the splitted 3-21G basis set; 37 for QR calculations of PtP we have used for platinum atom the so-called welltempered basis set ͑WTBS͒ of Huzinaga and Klobukowski. 39 The Franck-Condon ͑FC͒ factors are calculated through the excited state gradients in the B3LLYP/Lanl2DZ approach with the code developed by Macak et al 39 SOC integral calculations are performed with two approximations: scaled atomic charges proposed by Koseki et al 40 and with atomic mean field SOC two-electron integrals ͑AMFI͒. 41 Massweighted displacements along the active normal modes of e g symmetry are used for vibronic calculations.…”