Study in subatomic structure as extreme task for quantum mechanics

It is shown that the known task of single-electron atom can be established with its own solution of fine-structure constant. Moreover, this approach may relate to electron transition directly to the proton structure, that with a hyper-fine structure like the Lamb shift of hydrogen atom is specifically associated. Such highlighted result was expanded accordingly for the multiple-charge states, as beyond the existing classification of the Standard Model. Here is possible a certain prediction for the mass values by type the meson- boson particles. In particular, mass value for the Higgs boson has been modeled close enough to the experimental result. In this way a high-energy sequence for the exotic subatomic particles like the Higgs boson may be further revealed.

Exploration on performance of two-dimensional GaN photocathodes with uniform-doping and variable-doping structure

In this paper, the properties of two-dimensional (2D) gallium nitride (GaN) photocathodes with a uniform doping and variable doping structure are studied by using Mg as a doping element based on first principles. The stability, bandstructure, work function, density of state and optical properties of the GaN bilayer and GaN trilayer in two-doped ways are investigated. The results show that formation energy of variable doping structure is less than that of the uniform doping structure, which means that the variable doping structure is more stable. At the same time, the formation energy increases with increase of layers. The pristine GaN bilayer has an indirect bandgap, while the doped GaN bilayer transforms into a direct bandgap. The impurity levels appear in a forbidden band of doped GaN trilayers, which is favorable for electron transition. The results of work function reveal that variable doping structure has lower vacuum barriers and more electron escape numbers, which proves that it can improve the quantum efficiency of photocathodes. Finally, the analysis of optical properties shows that the uniform doping structure has better optical properties than that of the variable doping structure.

Classical physical mechanism of quantum production and its explanation for hydrogen atom structure and photoelectric effect

In this paper, the problems existing in the concepts of Planck's energy element and Einstein's light quantum are analyzed, and the alternate concept of quantum and a new concept of electron transition power were proposed. This paper clarifies the common misunderstanding in classical electromagnetics that the electron will radiate electromagnetic wave when it moves around the nucleus in a uniform circular motion and points out that the electron will radiate and absorb electromagnetic waves only when it moves around the nucleus in an accelerated or decelerated motion with a change of frequency and expounds the classical physical mechanism of quantum generation. Based on this, the quantization of electron orbital energy level of hydrogen atom and the phenomenon of spectrum are explained without Bohr's “quantization hypothesis.” In addition, the photoelectric effect is explained by using the modified quantum concept. The modified quantum concept and its mechanism of classical physics break the gap between macro and micro physics, eliminate the contradiction between “classical physics” and “quantum mechanics,” and lay an important foundation for the reconstruction of unified macro and micro physics.

Green Wavelength Femtosecond Laser Ablated Copper Surface

During green wavelength femtosecond laser ablation, d-band electrons are excited to become free and to participate in the absorption process. The increased electron temperature also induces the density of state shift and causes the gap between the d-band and the Fermi level to expand. The d-band electron transition effect during the laser ablation process causes nonlinear absorption, therefore, it should always be considered during simulations of laser-copper interaction.This study used a single femtosecond laser pulse with a wavelength of 515 nm and a pulse duration of 300 fs to ablate copper with fluence 0.7 - 63 J/cm2. The experimental results were compared with the theoretical results, where a modified Drude-critical point model was adopted to simulate the ablation depth. The modified model considered the electron transition effect and a two-temperature model that assumed both the linear and nonlinear absorption effect. Comparison of the experimental and simulated results revealed that the simulated ablation depth obtained using the nonlinear absorption model was consistent with the experimental results.

A Brief Study on Optical and Mechanical Properties of an Organic Material: Urea Glutaric Acid (2/1)—A Third Order Nonlinear Optical Single Crystal

Urea glutaric acid (UGA), an organic crystal, was synthesized and grown using a low temperature solution technique. Single crystal XRD revealed a monoclinic structure with a C2/C space group. The various cell data were identified. The optical parameters were calculated from UV-visible spectrum. The transmittance spectra showed the cutoff wavelength as 240 nm (low) and the energy gap determined from the spectra was compared with the theoretical energy gap. The transition number revealed the electron transition, which corresponded to direct allowed transition. The diverse optical parameters like reflectance, extinction coefficient, refractive index and optical susceptibility were determined. The least value of Urbach energy caused less defects and a good crystalline nature. The steepness value and electron phonon interaction were calculated. The positions of lower and higher band energy levels were identified. Electronic polarizability was found using the Clausius–Mossoti relation and tabulated. The mechanical fitness was measured from Vickers hardness analysis. The nonlinear optical property was measured from Z-scan analysis. Thus, the optical results support the material suitability and fitness for optical and electronic domain applications.

Effect of pH on synthesis, characterization and fluorescence behavior of WO3:Eu3 nano powders

WO3:Eu3+ nanoparticles with different pH values were prepared by citric acid method. The structure and morphology of nano-powders were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The luminescence properties of the nano-powders were tested by a fluorescence spectrometer. The results showed that the average particle size of the prepared WO3:Eu3+ nano powders were the smallest and reached 32 nm at pH = 1. Under different excitation wavelengths, the main emission peak of the sample was at 615 nm, corresponding to the 5D0 →7F2 electron transition of Eu3+. The emission intensity of WO3:Eu3+ nanoparticles prepared at pH = 5 was the highest at 615 nm.

Photophysical property and optical nonlinearity of cyclo[18]carbon (C18) precursors, C18-(CO)n (n = 2, 4, and 6): Focusing on the effect of carbonyl (-CO) groups

Considering their remarkable chemical stability, the precursors of cyclo[18]carbon (C18), C18-(CO)n (n = 2, 4, and 6), have more practical significance than the elusive C18 ring. In the present paper, the electronic spectrum and (hyper)polarizability of the C18-(CO)n (n = 2, 4, and 6) are studied by theoretical calculations and analyses for revealing the utility of introduction of carbonyl (-CO) groups on molecular optical properties. The analysis results show that the successive introduction of -CO groups leads to red-shift of the absorption spectrum, but maximum absorption of all molecules is mainly due to the charge redistribution caused by electron transition within C18 ring. Except for the vanishing first hyperpolarizability of C18-(CO)6 results from its octupolar character, the (hyper)polarizabilities of the precursors present an ascending trend with the increase of -CO groups in the molecule, and the higher-order response properties are more sensitive to the number of -CO groups. By means of (hyper)polarizability density analysis and (hyper)polarizability contribution decomposition, the fundamental reasons for the difference of (hyper)polarizability of different molecules were systematically discussed from the perspectives of physical and structural origins, respectively. As to the frequency dispersions under the incident light, the significant optical resonances were found on the hyperpolarizability of molecules C18-(CO)n (n = 2, 4, and 6), which contrast with the fact that it has inconspicuous influences on molecular polarizability.

The Relationship between the Spatial Arrangement of Pigments and Exciton Transition Moments in Photosynthetic Light-Harvesting Complexes

Considering bacteriochlorophyll molecules embedded in the protein matrix of the light-harvesting complexes of purple bacteria (known as LH2 and LH1-RC) as examples of systems of interacting pigment molecules, we investigated the relationship between the spatial arrangement of the pigments and their exciton transition moments. Based on the recently reported crystal structures of LH2 and LH1-RC and the outcomes of previous theoretical studies, as well as adopting the Frenkel exciton Hamiltonian for two-level molecules, we performed visualizations of the LH2 and LH1 exciton transition moments. To make the electron transition moments in the exciton representation invariant with respect to the position of the system in space, a system of pigments must be translated to the center of mass before starting the calculations. As a result, the visualization of the transition moments for LH2 provided the following pattern: two strong transitions were outside of LH2 and the other two were perpendicular and at the center of LH2. The antenna of LH1-RC was characterized as having the same location of the strongest moments in the center of the complex, exactly as in the B850 ring, which actually coincides with the RC. Considering LH2 and LH1 as supermolecules, each of which has excitation energies and corresponding transition moments, we propose that the outer transitions of LH2 can be important for inter-complex energy exchange, while the inner transitions keep the energy in the complex; moreover, in the case of LH1, the inner transitions increased the rate of antenna-to-RC energy transfer.