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Active Learning Configuration Interaction for Excited-State Calculations of Polycyclic Aromatic Hydrocarbons
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Cavity Quantum Electrodynamics Complete Active Space Configuration Interaction Theory
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Low-Lying Excited States of Linear All- Trans Polyenes: Insights from Analytic Gradient and Nonadiabatic Coupling Calculations Based on Multireference Configuration Interaction
Polyenes serve as a rigorous test for theoretical models and electronic structure methods, playing a key role in advancing computational and theoretical chemistry. Here, we present a high-level theoretical investigation of linear, all-trans polyenes using energy gradients and nonadiabatic coupling vectors based on an MR-CISD wave function to describe electronic transitions involving the ground state (1 1 A g – ) and three low-lying excited states (2 1 A g – , 1 1 B u + , and 2 1 B u – ) of hexatriene, octatetraene, and decapentaene. This approach enables accurate evaluation of both adiabatic and vertical excitation and emission energies, yielding results in excellent agreement with experiment, as well as locating minima on the crossing seam between adiabatic states. Our results show that vertical excitation energies to the 1 1 B u + state are blue-shifted by 0.2–0.3 eV relative to the experimental absorption maximum, whereas the vertical emission energy from the 2 1 A g – state is red-shifted by ∼0.2 eV relative to the experimental emission maximum. Upon relaxation from the Franck–Condon geometry, the 2 1 A g – state stabilizes by around 1 eV, compared to 0.2–0.3 eV for the 1 1 B u + state. An analysis of the S 1 /S 0 crossing seam in hexatriene shows that its minimum involves asymmetric backbone deformations and provides an efficient channel for ultrafast internal conversion to the ground state, consistent with the absence of detectable fluorescence in this molecule. These results demonstrate the power of analytic gradients and nonadiabatic coupling vectors based on an MR-CISD wave function for accurately characterizing the electronic structure and photophysics of polyenes.
Non-orthogonal Configuration Interaction Study on the Effect of Thermal Distortions on the Singlet Fission Process in Photoexcited Pure and B,N-Doped Pentacene Crystals
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Multiconfiguration self-consistent field and multireference configuration interaction methods and applications.
Abstract not provided
Tailoring Panchromatic Absorption and Excited-State Dynamics of Tetrapyrrole–Chromophore (Bodipy, Rylene) Arrays—Interplay of Orbital Mixing and Configuration Interaction
Here, whree sets of tetrapyrrole–chromophore arrays have been examined that exhibit panchromatic absorption across large portions of the near-ultraviolet (NUV) to near-infrared (NIR) spectrum along with favorable excited-state properties for use in solar-energy conversion. The arrays vary the tetrapyrrole (porphyrin, chlorin, bacteriochlorin), chromophore (boron-dipyrrin, perylene, terrylene), and attachment sites (meso-position, β-pyrrole position). In all, seven dyads, one triad, and nine benchmarks in toluene and benzonitrile were studied using steady-state and time-resolved absorption and fluorescence spectroscopy.
Analytic first derivatives of floating occupation molecular orbital-complete active space configuration interaction on graphical processing units
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