R. Telesca's research while affiliated with University of Groningen and other places

... The bandgap is one of the most important parameters determining possible applications of such conducting polymers [35][36][37][38][39]. A common strategy to predict the energy gap of infinite-chain conjugated polymers is to extrapolate the value of the HOMO-LUMO energy gap for increasing numbers of monomers in the oligomer chain [40][41][42][43]. The size of bandgaps often shows an approximately linear dependence on 1/n, allowing extrapolation to n → ∞ [44]. ...

... Excited state calculations and determination of excitation wavelengths are conducted through the application of TD-DFT. The relationship between excitation energy under EEF E exc , strength of EEF F, the variation amounts of the electric dipole moment Δμ and the polarization rate Δα can be described by the equation [25,26] where g i is the weighting factor equal to 1, s is the wave number, a 0 is Bohr radius. In the present investigation, diverse methods and basis sets are employed to optimize the molecular structure of C 6 H 5 I. ...

... The success of TDDFT depends critically on the choice of the functional employed, and it was shown that the combination with the standard numerical differentiation with respect to the external electric field also known as the finite field (FF) technique leads to reliable determination of the electric excess properties of uracil [12]. Previously, similar approach combining linear response (LR) version of TDDFT and the FF technique was used by Grozema et al. [13,14]. Before the proposed combination becomes a dependable and robust tool, more tests and comparisons with accurate wave function-based methods and experimental data are needed. ...

... The molecular response time is an equally important parameter, as it determines the temporal resolution of devices using the photochromic molecules as a photocontrol unit. 5 Most of the available diarylethenes feature time constants of ring opening/closure longer than a few picoseconds, [6][7][8][9][10][11][12][13][14] while we find that the molecule studied in this paper is characterized by the ring opening time constant below 600 fs. Rational design of fast photoswitches demands a deeper understanding of the mechanisms of electronic energy relaxation occurring during the photoreaction to be able to incorporate such features in the next generation of diarylethene-based switches. ...