“…(104 Note that the multiplicative ansatz used in (9) represents a zero-order perturbation term of the Born-Oppenheimer approximation [31]. It is valid only in the case of strongly separated electronic states.…”
Section: Basic Equations Ofthe Methodsmentioning
confidence: 99%
“…It is valid only in the case of strongly separated electronic states. Indeed, the function (9) approximately describes the electronphonon system in the vicinity of the adiabatic potential energy surface (APES) minima [31]. If we have a degenerate electronic state or a state lying nearby others in the energy scale (it means that several APESs are crossed or are close to each other at a point R), the coupling of vibronic states must be taken into account [31] and a sum of thc multiplicative terms is necessary.…”
A small-radius polaron model of the self-trapped hole (V,-center) in alkali halide crystals is presented. Along with the usual contributions, the electronic polarization is also included in accordance with the electronic polaron theory of Toyozawa. It is shown that the exact solution of the problem within the Landau-Pekar approximation leads to multi-hole quantum states accompanied by the relevant electronic and lattice polarizations. As an example the KCI crystal is considered, for which the V,-center structure as well as the self-trapping encrgy are computed. While solving our equations, the local symmetry of the defect is taken into account allowing us to consider a comparatively spread wave function of the hole. The results obtained demonstrate the importance of chemical-type interactions within the V,-center.
“…(104 Note that the multiplicative ansatz used in (9) represents a zero-order perturbation term of the Born-Oppenheimer approximation [31]. It is valid only in the case of strongly separated electronic states.…”
Section: Basic Equations Ofthe Methodsmentioning
confidence: 99%
“…It is valid only in the case of strongly separated electronic states. Indeed, the function (9) approximately describes the electronphonon system in the vicinity of the adiabatic potential energy surface (APES) minima [31]. If we have a degenerate electronic state or a state lying nearby others in the energy scale (it means that several APESs are crossed or are close to each other at a point R), the coupling of vibronic states must be taken into account [31] and a sum of thc multiplicative terms is necessary.…”
A small-radius polaron model of the self-trapped hole (V,-center) in alkali halide crystals is presented. Along with the usual contributions, the electronic polarization is also included in accordance with the electronic polaron theory of Toyozawa. It is shown that the exact solution of the problem within the Landau-Pekar approximation leads to multi-hole quantum states accompanied by the relevant electronic and lattice polarizations. As an example the KCI crystal is considered, for which the V,-center structure as well as the self-trapping encrgy are computed. While solving our equations, the local symmetry of the defect is taken into account allowing us to consider a comparatively spread wave function of the hole. The results obtained demonstrate the importance of chemical-type interactions within the V,-center.
“…2(a) and (b)) suggests the possible coupling between the hydrated electron and the pentagonal dodecahedral cluster THz-frequency ‘squashing’ and ‘twisting’ modes shown in Fig. 8(a) via the pseudo or dynamic Jahn–Teller (JT) effect (Bersuker and Polinger, 1989). Fig.…”
Laboratory generation of water nanoclusters from amorphous ice and strong terahertz (THz) radiation from water nanoclusters ejected from water vapour into a vacuum suggest the possibility of water nanoclusters ejected into interstellar space from abundant amorphous ice-coated cosmic dust produced by supernovae explosions. Water nanoclusters (section ‘Water nanoclusters’) offer a hypothetical scenario connecting major mysteries of our Universe: dark matter (section ‘Baryonic dark matter’), dark energy (section ‘Dark energy’), cosmology (section ‘Cosmology’), astrobiology (section ‘Astrobiology’) and the RNA world (section ‘The RNA world’) as the origin of life on Earth and habitable exoplanets. Despite their expected low density in space compared to hydrogen, their quantum-entangled diffuse Rydberg electronic states make cosmic water nanoclusters a candidate for baryonic dark matter that can also absorb, via the microscopic dynamical Casimir effect, the virtual photons of zero-point-energy vacuum fluctuations above the nanocluster cut-off vibrational frequencies, leaving only vacuum fluctuations below these frequencies to be gravitationally active, thus leading to a possible common origin of dark matter and dark energy. This picture includes novel explanations of the small cosmological constant, the coincidence of energy and matter densities, possible contributions of the red-shifted THz radiation from cosmic water nanoclusters at redshift z ≅ 10 to the cosmic microwave background (CMB) spectrum, the Hubble constant crisis, the role of water as a known coolant for rapid early star formation and ultimately, how life may have originated from RNA protocells on Earth and exoplanets and moons in the habitable zones of developed solar systems. Together, they lead to a cyclic universe cosmology – based on the proposed equivalence of cosmic water nanoclusters to a quintessence scalar field – instead of a multiverse based on cosmic inflation theory. Recent CMB birefringence measurements may support quintessence. Finally, from the quantum chemistry of water nanoclusters interacting with prebiotic organic molecules, amino acids and RNA protocells on early Earth and habitable exoplanets, this scenario is consistent with the anthropic principle that our Universe must have those properties which allow life, as we know it – based on water, to develop at the present stage of its history.
“…Such anomalies in the vicinity of T c were shown to be a rule for La 2−x Sr x CuO 4 , YBa 2 Cu 3 O 7−δ and Bi-Sr-Ca-Cu-O [8]. The co-operating (band) Jahn-Teller effect [9] can be the driving force for structural modulation [10,11], although the microscopical origin of the Jahn-Teller effect may give quite similar description of the CDW phase at the mean-field level.…”
In the present communication we propose a microscopic model to study the interplay between Jahn-Teller distortion and superconductivity in presence of impurity f-electron levels of rare-earth atoms and the hybridization between the impurity and the degenerate conduction electrons of Cu 2+ . The single particle electronic Green's functions are calculated by equations of motion and expressions for lattice strain (e) and superconducting gap (∆) are evaluated. The temperature dependence of ∆ and e are solved self-consistently by numerical methods. Both the gap parameters show mean-field behavior and very strong interaction between them. The superconducting order parameter is suppressed due to the presence of lattice distortion in the system and on the other hand the strain is suppressed in the temperature range of ∆. The effect of position of impurity level ( f )and the hybridization show many anomalous behavior.
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