Search results for "excited electronic states"
showing 4 items of 4 documents
A theoretical study of the lowest electronic states of azobenzene: the role of torsion coordinate in the cis-trans photoisomerization
2003
In the present paper we report the results of a multiconigurational computational study on potential- energy curves of azobenzene along the NN twisting to clarify the role of this coordinate in the decay of the S2(pp*) and S1(np*) states. We have found that there is a singlet state, S3 at the trans geometry, on the basis of the doubly excited coniguration n 2 p* 2 , that has a deep minimum at about 90 of twisting, where it is the lowest excited singlet state. The existence of this state provides an explanation for the short lifetime of S2(pp*) and for the wavelength-dependence of azobenzene photochem- istry. We have characterized the S1(np*) state by calcu- lating its vibrational frequencie…
Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states
2017
Abstract CaZrO3 (CZO) powders obtained by the polymeric precursor method at 400 °C, and then, the samples were annealed at different temperatures (400, 600, 800, and 1000 °C) and characterized by X-ray diffraction, Raman and ultraviolet–visible spectroscopic methods, along with photoluminescence (PL) emissions. First principle calculations based on the density functional theory (DFT), using a periodic cell models, provide a theoretical framework for understanding the PL spectra based on the localization and characterization of the ground and electronic excited states. Fundamental (singlet, s ) and excited (singlet, s* , and triplet, t* ) electronic states were localized and characterized us…
Internal conversion from excited electronic states of 229Th ions
2017
The process of internal conversion from excited electronic states is investigated theoretically for the case of the vacuum-ultraviolet nuclear transition of 229Th. Due to the very low transition energy, the 229Th nucleus offers the unique possibility to open the otherwise forbidden internal conversion nuclear decay channel for thorium ions via optical laser excitation of the electronic shell. We show that this feature can be exploited to investigate the isomeric state properties via observation of internal conversion from excited electronic configurations of Th+ and Th2+ ions. A possible experimental realization of the proposed scenario at the nuclear laser spectroscopy facility IGISOL in J…
Internal conversion from excited electronic states of 229Th ions
2017
The process of internal conversion from excited electronic states is investigated theoretically for the case of the vacuum-ultraviolet nuclear transition of 229 Th . Due to the very low transition energy, the 229 Th nucleus offers the unique possibility to open the otherwise forbidden internal conversion nuclear decay channel for thorium ions via optical laser excitation of the electronic shell. We show that this feature can be exploited to investigate the isomeric state properties via observation of internal conversion from excited electronic configurations of Th + and Th 2 + ions. A possible experimental realization of the proposed scenario at the nuclear laser spectroscopy facility IGISO…