Enhancement of Third-Order Nonlinear Response in Excited State of Metallophthalocyanines (PcM; M = H₂, Mg, Ni)

Abstract

In this paper we calculate the dynamic third-order nonlinear optical polarizabilities of three optical processes, third-harmonic generation, electric-field-induced second-harmonic generation, and degenerate four-wave mixing, for both ground and first excited singlet states in metal phthalocyanines in terms of the sum-over states formula. The transition moment elements and the transition energies in this formula are obtained using the INDO-SDCI method. The calculated second-order hypolarizabilities show a dispersion behavior with the difference from ground state and an enhancement of third-order nonlinear response in the first excited state. Among the PcM (M ) H 2 , Mg, Ni), there is a large enhancement of the first excited singlet state when there is a small third-order optical polarizability of the ground state. The calculated value of PcNi is compared with the observed one of the substituted PcNi in the order of magnitude. We also gain an understanding of enhancement mechanism for nonlinear processes in the excited state.

First-Principles Study of One- and Two-Photon Absorption of the H-Bonding Complexes from Monomeric Red Fluorescent Proteins with Large Stokes Shifts

“…However, electron correlation and exchange interactions are included in a natural way in the content of the time-dependent density functional theory (TDDFT) model . Accordingly, it is reasonable that the TDDFT method was employed to perform the excited state and γ calculations. , However, one should be also warned of the possibility of dangers in computational efforts. Although performing extensive checks of method and basis set dependence is rather limited, the reliability of the computational part is crucial of studies involving the determination of electric hyperpolarizabilities and related properties …”

Role of Structural Factors in the Nonlinear Optical Properties of Phthalocyanines and Related Compounds

“…Detailed calculations of the third-order hyperpolarizabilities have been recently reported. 119,120 The role of the central metal atom has been investigated in some experiments. [121][122][123][124][125] Incorporation of transition metals seems to strongly enhance the off-resonant χ (3) .…”

“…The model involving the ground 0 state and the 1 (Q band) and 2 (B band) excited states and a two-photon state 3 (one-photon transitions are parity-forbidden) has been found satisfactory to account for the response of centrosymmetric Pcs. Detailed calculations of the third-order hyperpolarizabilities have been recently reported. , …”

Strong nonlinear optical refractive effect of self-assembled multilayer films containing tetrasulfonated iron phthalocyanine

“…Phthalocyanines with two-dimensional 18 p-electron system have been intensively investigated as nonlinear optical (NLO) materials [1][2][3]. Their chemical variations through introduction of functional central atom and peripheral substituents can alter the electronic structure of the phthalocyanine (Pc) macrocycles, therefore, they allow the fine-tuning of the optical nonlinear response.…”