Electrostatic Field-Induced Oscillator Strength Focusing in Molecules

Abstract

The development of light-harvesting devices based on molecular materials depends critically on the ability to focus the electronic oscillator strength of molecules into the UV–vis spectral window. Typical molecular chromophores have only about 1% of their total electronic oscillator strength in this spectral region and thus perform at a small fraction of their possible effectiveness. This theoretical study finds that the electronic oscillator strength of polyenes in the UV–vis region may be enhanced by 1 order of magnitude using electrostatic fields, motivating specific experimental studies of oscillator strength focusing. We find scaling relationships between the polyene length, the intensity of the applied field, and the field-induced increase in oscillator strength that are useful for the implementation of light-harvesting strategies based on polyenes.

Photophysical Engineering of Fluorescent Proteins: Accomplishments and Challenges of Physical Chemistry Strategies

“…37 Few efforts have directly aimed to alter the absorption properties by tuning the oscillator strength of electronic transitions in FPs, but initial results in this direction are promising. 44,45 In a recent study, Mysǩováand co-workers determined transition dipole moments of absorption (xTDM) and emission (mTDM) of several well-studied, bright FPs. 46 Their approach combined cryogenic X-ray crystallography with room-temperature polarized optical transmission and fluorescence measurements to determine the orientation of these dipole moments.…”

Tuning the Optical Band Gap of Semiconductor Nanocomposites—A Case Study with ZnS/Carbon

“…Fields originating from defects may even limit the linewidth of excitonic emission [6]. In molecular systems these effects are well documented and have been analyzed also theoretically [7]. Since most composites are applied and used inside a matrix, the interaction strength is depending strongly on the effective dielectric properties of the environment, which in many cases is containing water and therefore will be a complex ensemble of solids (with typical relative permittivities on the order of 10 or below like for ZnS) and liquids or even air.…”

Comment on “Applicability of perturbed matrix method for charge transfer studies at bio/metallic interfaces: a case of azurin” by O. Kontkanen, D. Biriukov and Z. Futera, Phys. Chem. Chem. Phys., 2023, 25, 12479

“…This observation raises the question of whether high polarizability, coupled to a strong intraprotein electric field, is essential for the function of charge transport performed by these cofactors. Strong dependence of polarizabilities of conjugated molecules on conformation, 22 charge state, 21,22 and external electric field 4,53 was noted in the past and might be relevant to function performed by these cofactors.…”

“…As a manifestation of the medium effect, the integrated OS was found to increase in polyenes when an external electric field was applied along the chain. 53 Likewise, changes of azurin absorption spectra with pH 31 (dashed line in Fig. 1) point to a 0 being affected by the local protein field.…”