5s correlation confinement resonances in Xe-endo-fullerenes

Spectacular trends in the modification of the Xe 5s photoionization via interchannel coupling with confinement resonances emerging in the Xe 4d giant resonance upon photoionization of the Xe@C60, Xe@C240 and Xe@C60@C240 endo-fullerenes are theoretically unraveled and interpreted.Comment: 1 page, 1 figure. 2011 International Conference on Photonic, Electronic, and Atomic Collisions (Belfast, UK, 2011). Paper number We15

Xe 4d photoionization in Xe@C60, Xe@C240, and Xe@C60@C240

Re-evaluated parameters for the square-well potential model for photoionization of endo-fullerenes are proposed and employed to reveal the spectacular modifications in the Xe 4d photoionization giant resonance along the path from Xe@C60 to Xe@C240 to multi-walled Xe@[email protected]: 1 page, 1 figure. 2011 International Conference on Photonic, Electronic, and Atomic Collisions (Belfast, UK, 2011), abstract Tue13

Confinement and electron correlation effects in photoionization of atoms in endohedral anions: Ne@C60^{z-}

Trends in resonances, termed confinement resonances, in photoionization of atoms A in endohedral fullerene anions A@C60^{z-} are theoretically studied and exemplified by the photoionization of Ne in Ne@C{60}^{z-}. Remarkably, above a particular nl ionization threshold of Ne in neutral Ne@C60 (I_{nl}^{z=0}), confinement resonances in corresponding partial photoionization cross sections sigma_{nl} of Ne in any charged Ne@C60^{z-} remain almost intact by a charge z on the carbon cage, as a general phenomenon. At lower photon energies, omega < I_{nl}^{z=0}, the corresponding photoionization cross sections develop additional, strong, z-dependent resonances, termed Coulomb confinement resonances, as a general occurrence. Furthermore, near the innermost 1s ionization threshold, the 2p photoionization cross section sigma_{2p} of the outermost 2p subshell of thus confined Ne is found to inherit the confinement resonance structure of the 1s photoionization spectrum, via interchannel coupling. As a result, new confinement resonances emerge in the 2p photoionization cross section of the confined Ne atom at photoelectron energies which exceed the 2p threshold by about a thousand eV, i.e., far above where conventional wisdom said they would exist. Thus, the general possibility for confinement resonances to resurrect in photoionization spectra of encapsulated atoms far above thresholds is revealed, as an interesting novel general phenomenon.Comment: 6 pages, 4 figures, Latex2e, jpconf.cls styl

Diffuse versus square-well confining potentials in modelling AA@C60_{60} atoms

Attention: this version-$2$ of the manuscript differs from its previously uploaded version-$1$ (arXiv:1112.6158v1) and subsequently published in 2012 J. Phys. B \textbf{45} 105102 only by a removed typo in Eq.(2) of version-$1$; there was the erroneous factor "2" in both terms in the right-hand-side of the Eq.(2) of version-$1$. Now that the typo is removed, Eq.(2) is correct. A perceived advantage for the replacement of a discontinuous square-well pseudo-potential, which is often used by various researchers as an approximation to the actual C$_{60}$ cage potential in calculations of endohedral atoms $A$@C$_{60}$, by a more realistic diffuse potential is explored. The photoionization of endohedral H@C$_{60}$ and Xe@C$_{60}$ is chosen as the case study. The diffuse potential is modelled by a combination of two Woods-Saxon potentials. It is demonstrated that photoionization spectra of $A$@C$_{60}$ atoms are largely insensitive to the degree $\eta$ of diffuseness of the potential borders, in a reasonably broad range of $\eta$'s. Alternatively, these spectra are found to be insensitive to discontinuity of the square-well potential either. Both potentials result in practically identical calculated spectra. New numerical values for the set of square-well parameters, which lead to a better agreement between experimental and theoretical data for $A$@C$_{60}$ spectra, are recommended for future studies.Comment: 11 pages, 4 figure

Relativistic calculations of angular dependent photoemission time delay

Angular dependence of photoemission time delay for the valence $np_{3/2}$ and $np_{1/2}$ subshells of Ar, Kr and Xe is studied in the dipole relativistic random phase approximation. Strong angular anisotropy of the time delay is reproduced near respective Cooper minima while the spin-orbit splitting affects the time delay near threshold

Development and research of data transmission system using M-sequence

В исследовании синтезируется система передачи данных высокой помехозащищенности. Разработаны передающее и приемное устройства, реализующие метод расширения спектра, осуществляющие кодирование и декодирование передаваемого сообщения М-последовательностью. Схемы синтезированы в среде SysGen, эксперимент проведен на ПЛИС фирмы XILINX семейства Kintex7. Получение данных передатчиком осуществлялось с помощью стандарта «UART» со скоростью передачи 1,5 Мб/с. Эксперимент установил, что работоспособность системы ограничивается отношением мощности сигнала и помехи равной -14 дБ.A data transmission system with high noise immunity is synthesized. Transmitting and receiving devices, implementing the spread spectrum and carrying out transmitted message encoding and decoding by m‑sequence, are designed. Schemes are synthesized by using the SysGen software. The experiment is performed with Kintex7 PLD developed by XILINX. The system is based on the use of the standard «UART» with a rate of 1.5 Mbit/s. The experiment found that the system performance is limited by the signal-to-noise ratio equaled to -14 dB

Secure radio communication systems using encoded signal in time, frequency and phase

The original algorithm of transfer 8-bit digital data with use of signal, discretely-encoded in the timing, frequency and phase using the matrix of Costas and of Walsh functions, providing high reserve of work and security from broadband and narrow-band interferences is developed. The algorithms of generation and processing of signals on the receiving side is realized in FPGA of type XC7k325T (Xilinx).A radio communication system on the SDR technology (software defined radio) on the basis of the AD 9361 transceiver (Analog Devices).Разработан оригинальный алгоритм передачи 8-бит цифровых данных с использованием сигнала, дискретно-кодированного по времени, частоте и фазе с помощью матрицы Костаса и функций Уолша. Обеспечивается высокая скрытность работы и защищенность от широкополосных и узкополосных помех. Алгоритмы формирования сигналов и обработки их на приемной стороне реализованы в ПЛИС типа XC7k325T (Xilinx). Система радиосвязи реализована по технологии SDR (программно определяемое радио) на основе трансивера AD 9361 (Analog Devices)