Two-photon absorption in host-guest complexes

Abstract

We present an extensive analysis of one-and two-photon absorption processes in some organic hostguest (H-G) complexes using linear and quadratic response theory within the framework of timedependent density functional theory. For this purpose, we have considered all possible 20 host-guest complexes constructed from 4 host and 5 guest molecules. We have analysed how the one-and two-photon activity of the host and guest molecules are transferred to the respective host-guest complexes and how the electron donating and electron accepting ability of host-guest complexes affect their two-photon activity. Based on an analysis using the concept of channel interference, we have performed an in-depth analysis of the two-photon absorption processes in all these systems and provided a microscopic explanation for their variation among different complexes.

Why does the orientation of azulene affect the two-photon activity of a porphyrinoid–azulene system?

“…No imaginary frequency is found for any of them confirming their validity as the minimum energy geometry on their respective potential energy surfaces. One-and two-photon absorption [46][47][48][49] (OPA and TPA) cross-sections for the first five singlet states are computed at the RICC2/cc-pVDZ 50,51 level of theory as implemented in the Turbomole 7.3 52,53 package. Furthermore, to study the chargetransfer character of the electronic excitations in the said systems, natural transition orbitals (NTOs) [54][55][56] are generated at the RICC2/cc-pVDZ level of theory using the Turbomole 7.3 package, and the density-difference plot and charge-transfer distance parameter are computed at the MN15 57,58 / 6-311+G(d,p) level of theory as implemented in the Gaussian 16 program package.…”

A Curious Case of Two‐Photon Absorption in n‐Helicene and n‐Phenylene, n=6–10: Why n=7 is Different?

“…[3] Lately, there has been significant research interest in materials exhibiting substantial two-photon absorption (TPA), a second-order non-linear optical (NLO) property. [20][21][22][23][24][25][26][27][28] This heightened interest is driven by the promising applications of such materials across various domains, including the development of high-power lasers, applications in photodynamic therapy, drug photoactivation, the design of optical limiting devices, and numerous other potential uses. [29] Researchers are actively investigating TPA characteristics in twisted and nonplanar conjugated molecules to advance the development of materials with augmented TPA capabilities.…”