We present a quantum-mechanical theory to study excitation energy transfers between molecular systems in solution. The model is developed within the time-dependent (TD) density-functional theory and the solvent effects are introduced in terms of the polarizable continuum model (PCM). Unique characteristic of this model is that both "reaction field" and screening effects are included in a coherent and self-consistent way. This is obtained by introducing proper solvent-specific operators in the Kohn-Sham equations and in the corresponding TD scheme. The solvation model exploits the integral equation formalism (IEF) version of PCM and it defines the solvent operators on a molecular cavity modeled on the real three-dimensional (3D) structure of the solute systems. Applications to EET in dimers of ethylene and naphtalene are presented and discussed.
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http://dx.doi.org/10.1063/1.1669389 | DOI Listing |
Sci Rep
January 2025
Laser Research Center, Vilnius University, Saulėtekio Avenue 10, LT-10223, Vilnius, Lithuania.
We present a comparative experimental study of supercontinuum generation in undoped scintillator crystals: bismuth germanate (BGO), yttrium orthosilicate (YSO), lutetium oxyorthosilicate (LSO), lutetium yttrium oxyorthosilicate (LYSO) and gadolinium gallium garnet (GGG), pumped by 180 fs fundamental harmonic pulses of an amplified Yb:KGW laser. In addition to these materials, experiments in yttrium aluminium garnet (YAG), potassium gadolinium tungstate (KGW) and lithium tantalate (LT) were performed under identical experimental settings (focusing geometry and sample thickness), which served for straightforward comparison of supercontinuum generation performances. The threshold and optimal (that produces optimized red-shifted spectral extent) pump pulse energies for supercontinuum generation were evaluated from detailed measurements of spectral broadening dynamics.
View Article and Find Full Text PDFNat Commun
January 2025
Institute for Materials Science, University of Stuttgart, D-70569, Stuttgart, Germany.
The knowledge of diffusion mechanisms in materials is crucial for predicting their high-temperature performance and stability, yet accurately capturing the underlying physics like thermal effects remains challenging. In particular, the origin of the experimentally observed non-Arrhenius diffusion behavior has remained elusive, largely due to the lack of effective computational tools. Here we propose an efficient ab initio framework to compute the Gibbs energy of the transition state in vacancy-mediated diffusion including the relevant thermal excitations at the density-functional-theory level.
View Article and Find Full Text PDFAppl Radiat Isot
December 2024
Department of Medical Physics University of Wisconsin School of Medicine and Public Health, Madison, WI, 53705, USA. Electronic address:
This work reports experimental Ge(d,n)As cross sections producing Arsenic-71 (t = 65.3 h, 28% β), a potentially useful diagnostic radionuclide. Target stacks containing two Ge foils, a Ni monitor foil, and an Al degrader were irradiated with 5.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Chemistry, KAIST, Daejeon, Republic of Korea.
Despite its profound significance, the molecular structural changes near the transition state, driven by the vibronic coupling, have remained largely unexplored, leaving a crucial aspect of chemical reactions shrouded in uncertainty. Herein, the dynamical behavior of the reactive flux on the verge of chemical bond breakage was revealed through the spectroscopic characterization of a large amplitude vibrational motion. Highly excited internal rotor states of S methylamine (CHND) report on the structural change as the molecule approaches the transition state, indicating that the quasi-free internal rotation is strongly coupled to the reaction coordinate as their energies near the maximum of the reaction barrier for the N-D chemical bond predissociation.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
HUN-REN Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary.
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