Replication Data for: Fully Polarizable QM/Fluctuating Charge Approach to Two-Photon Absorption of Aqueous Solutions

This dataset contains raw input and output files for the LSDALTON calculations reported in \"Fully Polarizable QM/Fluctuating Charge Approach to Two-Photon Absorption of Aqueous Solutions\". The version of LSDALTON used for this paper uses three input files: - a .dal file with input directives for the quantum mechanical calculation. - a .mol file with the cartesian coordinates of the target molecule in the focuses model. This file also specifies the Gaussian basis set. - a .pcm file with the input directives for the classical environment. The names of the various output files follow from the names of the input files according to these following scheme: ___4_2_10.out the portion is only present for the calculations with the solvent models. The numeric suffix refers to the parallel set up of the calculations.
We present the extension of the quantum/classical polarizable fluctuating charge model to the calculation of single residues of quadratic response functions, as required for the computational modeling of two-photon absorption cross-sections. By virtue of a variational formulation of the quantum/classical polarizable coupling, we are able to exploit an atomic orbital-based quasienergy formalism to derive the additional coupling terms in the response equations. Our formalism can be extended to the calculation of arbitrary order response functions and their residues. The approach has been applied to the challenging problem of one- and two-photon spectra of rhodamine 6G (R6G) in aqueous solution. Solvent effects on one- and two-photon spectra of R6G in aqueous solution have been analyzed by considering three different approaches, from a continuum (QM/PCM) to two QM/MM models (non-polarizable QM/TIP3P and polarizable QM/FQ). Both QM/TIP3P and QM/FQ simulated OPA and TPA spectra show that the inclusion of discrete water solvent molecules is essential to increase the agreement between theory and experiment. QM/FQ has been shown to give the best agreement with experiments.