Resonance enhanced electron impact excitation for P-like Cu XV

Employing both the Dirac R-matrix and the relativistic distorted wave with independent process and isolated reso- nance approaches, we report resonance enhanced electron impact excitation data （specifically, effective collision strengths） among the lowest 41 levels from the n = 3 configurations of Cu XV. The results show that the latter approach can obtain resonance contributions reasonably well for most excitations of Cu XV, though a comparison between the two approaches shows that the close-coupling effects are truly significant for rather weak excitations, especially for two-electron excitations from the 3s3p4 to 3s23p23d configuration. Resonance contributions are significant （more than two orders of magnitude） for many excitations and dramatically influence the line intensity ratios associated with density diagnostics.

On rotational normal modes of the Earth：Resonance,excitation,convolution, deconvolution and all that

Earth＇s Coriolis force profoundly alters the eigen frequencies, eigen functions, and excitation of rotational normal modes. Some rotational modes of the solid mantle-fluid outer core-solid inner core Earth system are confirmed observationally and some remain elusive. Here we bring together from literature assertions about an excited resonance system in terms of the Green＇s function and temporal convolution. We raise caveats against taking the face values of the oscillational motion which have been ＂masqueraded＂ by the convolution, necessitating deconvolution for retrieving the excitation function which reflects the true variability. Lastly we exemplify successful applications of the deconvolution in estimating resonance complex frequencies.

Excitation of Zonal Flows by ion-temperature-gradient Modes Excited by the Fluid Resonance

We apply the reductive perturbation method to the simple electrostatic ion-temperature-gradient mode in an advanced fluid description. The fluid resonance turns out to play a major role for the excitation of zonal flows. This is the mechanism recently found to lead to the low-to-high （L-H） mode transition and to the nonlinear Dimits upshift in transport code simulations. It is important that we have taken the nonlinear temperature dynamics from the Reynolds stress as the convected diamagnetic flow. This has turned out to be the most relevant effect as found in transport simulations of the L-H transition, internal transport barriers and Dimits shift. This is the first time that an analytical method is applied to a system which numerically has been found to give the right experimental dynamics.

Relaxation of Ne^(1+)1s^(0)2s^(2)2p^(6)np produced by resonant excitation of an ultraintense ultrafast x-ray pulse

The creation and relaxation of double K-hole states 1s^(0)2s^(2)2p^(6)np(n≥3)of Ne^(1+)in the interaction with ultraintense ultrafast x-ray pulses are theoretically investigated.The x-ray photon energies are selected so that x-rays first photoionize1s^(22)s^(22)p^(6) of a neon atom to create a single K-hole state of 1s2s^(22)p^(6) of Ne^(1+),which is further excited resonantly to double K-hole states of ls^(0)2s^(2)2p^(6)np(n≥3).A time-dependent rate equation is used to investigate the creation and relaxation processes of 1s^(0)2s^(2)2p^(6)np,where the primary microscopic atomic processes including photoexcitation,spontaneous radiation,photoionization and Auger decay are considered.The calculated Auger electron energy spectra are compared with recent experimental results,which shows good agreement.The relative intensity of Auger electrons is very sensitive to the photon energy and bandwidth of x-ray pulses,which could be used as a diagnostic tool for x-ray free electron laser and atom experiments.

A piezoelectric energy harvester based on internal resonance

A vibration-based energy harvester is essentially a resonator working in a limited frequency range.To increase the working frequency range is a challenging problem.This paper reveals a novel possibility for enhancing energy harvesting via internal resonance.An internal resonance energy harvester is proposed.The excitation is successively assumed as the Gaussian white noise,the colored noise defined by a second-order filter,the narrow-band noise,and exponentially correlated noise.The corresponding averaged root-meansquare output voltages are computed.Numerical results demonstrate that the internal resonance increases the operating bandwidth and the output voltage.

Dielectronic recombination and resonant transfer excitation processes for helium-like krypton

The relativistic configuration interaction method is employed to calculate the dielectronic recombination（DR） cross sections of helium-like krypton via the 1s2lnl ＇（n = 2,3,...,15） resonances.Then,the resonant transfer excitation（RTE） processes of Kr 34＋ colliding with H,He,H 2,and CH x（x = 0-4） targets are investigated under the impulse approximation.The needed Compton profiles of targets are obtained from the Hartree-Fock wave functions.The RTE cross sections are strongly dependent on DR resonant energies and strengths,and the electron momentum distributions of the target.For H 2 and H targets,the ratio of their RTE cross sections changes from 1.85 for the 1s2l2l ＇ to 1.88 for other resonances,which demonstrates the weak molecular effects on the Compton profiles of H 2.For CH x（x = 0-4） targets,the main contribution to the RTE cross section comes from the carbon atom since carbon carries 6 electrons;as the number of hydrogen increases in CH x,the RTE cross section almost increases by the same value,displaying the strong separate atom character for the hydrogen.However,further comparison of the individual orbital contributions of C（2p,2s,1s） and CH 4（1t 2,2a 1,1a 1） to the RTE cross sections shows that the molecular effects induce differences of about 25.1%,19.9%,and 0.2% between 2p-1t 2,2s-2a 1,and 1s-1a 1 orbitals,respectively.

Xe-Kr laser induced collisional ionization system and experimental preparation of its initial state: Four-photon resonant excitation

This paper proposes a novel one-colour Xe-Kr laser induced collisional ionization system. Considering the level scheme of the system, it finds that the initial state of the reaction--the four 4f levels with even J of Xe-can be prepared through method of four-photon resonant excitation by dye laser with wavelength of -440 nm. Absorption of an additional photon （the transfer laser） of the same wavelength will complete the laser induced collisional ionization process. The resonance enhanced ionization spectrum of Xe by four laser photons at -440nm is measured through time-of-flight mass spectrometry, this aims at the preparation of the initial state of the system proposed. The Stark broadening of the measured spectrum is observed and consistent with the previous study. Analysis of the measured resonance ionization spectrum implies the feasibility of -440 nm four-photon resonant excitation of the initial 4f state of the Xe Kr system proposed in this paper, which prepares for a further experiment of laser induced collisional ionization.

Exploration of magnetic field generation of H_(3)^(2+)by direct ionization and coherent resonant excitation

Coherent electronic dynamics are of great significance in photo-induced processes and molecular magnetism.We theoretically investigate electronic dynamics of triatomic molecule H_(3)^(2+) by circularly polarized pulses,including electron density distributions,induced electronic currents,and ultrafast magnetic field generation.By comparing the results of the coherent resonant excitation and direct ionization,we found that for the coherent resonant excitation,the electron is localized and the coherent electron wave packet moves periodically between three protons,which can be attributed to the coherent superposition of the ground A′state and excited E+state.Whereas,for the direct single-photon ionization,the induced electronic currents mainly come from the free electron in the continuum state.It is found that there are differences in the intensity,phase,and frequency of the induced current and the generated magnetic field.The scheme allows one to control the induced electronic current and the ultrafast magnetic field generation.

Nuclear dissociation after the O 1s→(^(4)Σ_(u)^(-))3sσexcitation in O_(2)molecules

We investigate the dissociation dynamics of core-excited O_(2)molecules using a high-resolution energy-resolved electron-ion coincidence experimental setup.The excited cationic states with two valence holes and one Rydberg electron are created after spectator Auger decay induced by O 1s→(^(4)Σ_(u)^(-))3sσcore excitation in O_(2).From the energy correlation between the kinetic energy of the Auger electron and the ion kinetic energy release,we distinguish several dissociation channels.Rather complex dissociation channels of the spectator Auger final states are disclosed,which can be explained by the increased number of the crossing point due to the existence of Rydberg electron.The quantum system will evolve into different dissociation limits at each crossing point between the potential energy curves.

Resonances Characteristics of Parallel Plate Waveguide Cavities

The influence of air gaps on the response of transmission for a transverse-electric mode parallel-plate waveguide（TE-PPWG） with a single cavity and double cavities has been studied experimentally. As the air gap is larger than the resonant wavelength of high order cavity mode in the single deep grooved waveguide, only the fundamental cavity mode can be excited and single resonance can be observed in the transmission spectrum. Based on above observations, a tunable multiband terahertz（THz）notch filter has been proposed and the variation of air gap has turned out to be an effective method to select the band number. Experimental data and simulated results verify this band number tunability. This mechanical control mechanism for electromagnetic induced transparency（EIT） will open a door to design the tunable THz devices.

Phonon-assisted excitation energy transfer in photosynthetic systems

The phonon-assisted process of energy transfer aiming at exploring the newly emerging frontier between biology and physics is an issue of central interest.This article shows the important role of the intramolecular vibrational modes for excitation energy transfer in the photosynthetic systems.Based on a dimer system consisting of a donor and an acceptor modeled by two two-level systems,in which one of them is coupled to a high-energy vibrational mode,we derive an effective Hamiltonian describing the vibration-assisted coherent energy transfer process in the polaron frame.The effective Hamiltonian reveals in the case that the vibrational mode dynamically matches the energy detuning between the donor and the acceptor,the original detuned energy transfer becomes resonant energy transfer.In addition,the population dynamics and coherence dynamics of the dimer system with and without vibration-assistance are investigated numerically.It is found that,the energy transfer efficiency and the transfer time depend heavily on the interaction strength of the donor and the high-energy vibrational mode,as well as the vibrational frequency.The numerical results also indicate that the initial state and dissipation rate of the vibrational mode have little influence on the dynamics of the dimer system.Results obtained in this article are not only helpful to understand the natural photosynthesis,but also offer an optimal design principle for artificial photosynthesis.

Experimental Analysis of Dynamic Stiffness Coefficient of the New Mn-Cu Alloy Annular Parts

Based on excitation-resonance mass testing principle, a proper experiment testing system is designed for annular parts. The dynamics characters of the axis sleeve, which is made of a new Mn-Cu alloy and used as a vibration reductor in high acceleration rotary testing machine for fusee, is investigated. The relationship between stiffness coefficient and utilizing frequency is obtained, and the simplified dynamics model of crystal is established From the viewpoint of crystal microstructure of the Mn-Cu alloy, the experiment result is analyzed by the viscoelastic theory, and the characters of stress and strain in the condition of high frequency are discussed. The results indicate that the Mn-Cu alloy annular parts are fit to be used on the high accleration rotary testing machine for fusee.

Coupled extension and thickness-twist vibrations of lateral field excited AT-cut quartz plates

In this paper, the coupled extension and thickness- twist vibrations are studied for AT-cut quartz plates under Lateral Field Excitation （LFE） with variations along the x1- direction. Mindlin＇s two-dimensional equations are used for anisotropic crystal plates. Both free and electrically forced vibrations are considered. Important vibration characteristics are obtained, including dispersion relations, frequency spectra, and motional capacitances. It is shown that, to avoid the effects of the couplings between extension and thickness-twist vibrations, a series of discrete values of the length/thickness ratio of the crystal plate need to be excluded. The results are of fundamental significance for the design of LFE resonators and sensors.

Autoionization spectra of Sm atom

Spectra of autoionizing states of the Sm atom in an energy region between 45948.9 cm^-1 and 46943.6 cm^-1 are systematically investigated by a three-color multi-step resonant excitation scheme with three different excitation paths.The three intermediate states,4f 66s7s 7F3,4f 66s7s 7F4,and 4f 66s7s 9F5 are employed for the three paths,respectively.Based on precise calibration of wavelength,the level energies of 112 autoionizing states are determined with the line widths and the relative line intensities of the related transitions.The possible influence of configuration interaction on the line shape of autoionizing state is also discussed.In addition,a unique value of J,the total angular momentum,is assigned to all detected states by comparing the three spectra obtained with the different excitation paths.

Thermal emission properties of one-dimensional grating with different parameters

Thermal emission is often presented as a typical incoherent process. Incorporating periodic structures on the tungsten surface offers the possibility to obtain coherent thermal emission sources. Here we illustrate grating as an example to examine the influence of the geometric parameters on the thermal emission properties. It is found that for very shallow gratings, only surface plasmon polariton（SPP） modes can be excited and the emission efficiency is closely related with the filling factor. When the ratio of the depth to period of the grating is in the range from 1/20 to 1/2, the field between the adjacent corners can be coupled to each other across the air gap for the filling factor larger than 0.5 and produce a similar resonance as in an air rod. Further increase of the grating depth can cause the groove of the grating forming metal–insulator–metal（MIM） structures and induce surface plasmon standing wave modes. Our investigations will not only be helpful for manipulating thermal emission properties according to applications, but also help us understand the coupling mechanism between the incident electromagnetism waves and gratings with different parameters in various research fields.

Spin noise spectroscopy of rubidium atomic gas under resonant and non-resonant conditions

The spin fluctuation in rubidium atom gas is studied via all-optical spin noise spectroscopy（SNS）.Experimental results show that the integrated SNS signal and its full width at half maximum（FWHM） strongly depend on the frequency detuning of the probe light under resonant and non-resonant conditions.The total integrated SNS signal can be well fitted with a single squared Faraday rotation spectrum and the FWHM dependence may be related to the absorption profile of the sample.

Rydberg state excitation in molecules manipulated by bicircular two-color laser pulses

Multiphoton resonant excitation and frustrated tunneling ionization,manifesting the photonic and optical nature of the driving light via direct excitation and electron recapture,respectively,are complementary mechanisms to access Rydberg state excitation(RSE)of atoms and molecules in an intense laser field.However,clear identification and manipulation of their individual contributions in the light-induced RSE process remain experimentally challenging.Here,we bridge this gap by exploring the dissociative and nondissociative RSE of H2 molecules using bicircular two-color laser pulses.Depending on the relative field strength and polarization helicity of the two colors,the RSE probability can be boosted by more than one order of magnitude by exploiting the laser waveform-dependent field effect.The role of the photon effect is readily strengthened with increasing relative strength of the second-harmonic field of the two colors regardless of the polarization helicity.As compared to the nondissociative RSE forming H2
,the field effect in producing the dissociative RSE channel of eHt;H
T is moderately suppressed,which is primarily accessed via a three-step sequential process separated by molecular bond stretching.Our work paves the way toward a comprehensive understanding of the interplay of the underlying field and photon effects in the strong-field RSE process,as well as facilitating the generation of Rydberg states optimized with tailored characteristics.

为像氦的克的 Dielectronic 再结合和反响的转移刺激过程

The relativistic configuration interaction method is employed to calculate the dielectronic recombination(DR) cross sections of helium-like krypton via the 1s2lnl ’(n = 2,3,...,15) resonances.Then,the resonant transfer excitation(RTE) processes of Kr 34+ colliding with H,He,H 2,and CH x(x = 0-4) targets are investigated under the impulse approximation.The needed Compton profiles of targets are obtained from the Hartree-Fock wave functions.The RTE cross sections are strongly dependent on DR resonant energies and strengths,and the electron momentum distributions of the target.For H 2 and H targets,the ratio of their RTE cross sections changes from 1.85 for the 1s2l2l ’ to 1.88 for other resonances,which demonstrates the weak molecular effects on the Compton profiles of H 2.For CH x(x = 0-4) targets,the main contribution to the RTE cross section comes from the carbon atom since carbon carries 6 electrons;as the number of hydrogen increases in CH x,the RTE cross section almost increases by the same value,displaying the strong separate atom character for the hydrogen.However,further comparison of the individual orbital contributions of C(2p,2s,1s) and CH 4(1t 2,2a 1,1a 1) to the RTE cross sections shows that the molecular effects induce differences of about 25.1%,19.9%,and 0.2% between 2p-1t 2,2s-2a 1,and 1s-1a 1 orbitals,respectively.

Resonant four-photon photoemission from SnSe_(2)(001)

High-order nonlinear multiphoton absorption is usually inefficient,but can be enhanced by designing resonant excitations between occupied and unoccupied energy levels.We conducted angle-resolved multi-photon photoemission(mPPE)studies on the SnSe_(2)(001)surfaces excited by ultrashort laser pulses.By tuning photon energy and light polarization,we demonstrate the presence of a resonant four-photon photoemission(4PPE)process involving the occupied valence band(VB),the unoccupied second conduction band(CB2)and the unoccupied image-potential state(IPs)of SnSe_(2).In this 4PPE process,VB electrons of SnSe_(2) are resonantly excited into CB2 by adsorbing two photons,followed by the adsorption of another photon to populate the n=1 IPs before being emitted out to the vacuum by adsorbing one more photon.This results in a double-resonant 4PPE process,which exhibits approximately a 40 times enhancement in photoemission yields compared to cases where one of the resonant pathways,CB2→IPs,is inhibited by involving a virtual state instead of the IPs in the 4PPE.The double-resonant 4PPE process efficiently excite the bulk VB electrons outside the vacuum,like taking advantage of resonant“ladders”through two real empty electronic states of SnSe_(2).Our results highlight the important applications of mPPE in probing the band-structure,particularly the unoccupied states,of recently emerging main group dichalcogenide semiconductors.Furthermore,the discovered resonant mPPE process contributes to the exploration of their promising optoelectronic applications.

Multiple resonant excitations of surface plasmons in a graphene stratified slab by Otto configuration and their independent tuning

Multiple resonant excitations of surface plasmons in a graphene stratified slab are realized by Otto configuration at terahertz frequencies. The proposed graphene stratified slab consists of alternating dielectric layers and graphene sheets, and is sandwiched between a prism and another semi-infinite medium. Optical response and field distribution are determined by the transfer matrix method with the surface current density boundary condition.Multiple resonant excitations appear on the angular reflection spectrum, and are analyzed theoretically via the phase-matching condition. Furthermore, the effects of the system parameters are investigated. Among them, the Fermi levels can tune the corresponding resonances independently. The proposed concept can be engineered for promising applications, including angular selective or multiplex filters, multiple channel sensors, and directional delivery of energy.