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Circularly and elliptically polarized high-order harmonics have unique advantages when used in studying the chiral and magnetic features of matters. Here, we studied the polarization properties of high-order harmonic generated from alignment nitrogen molecules driven by cross-linearly-polarized two-color laser fields. Through adjusting various laser parameters and targets, such as the relative phase, the crossing angle, the intensity ratio of driving fields, and the molecular alignment angle, we obtained highly elliptically polarized high-order harmonics with the same helicity in a wide spectral range. It provides a possible and effective way to generate elliptically polarized attosecond pulses. Finally, we show the probability of controlling the spectral range of elliptically polarized harmonics.

We have studied the vortex dynamics of CaKFe4As4 single crystals using a dynamical magnetization relaxation method. A large region of vortex elastic motion is observed indicating strong vortex pinning ability. Temperature dependence of normalized flux pinning energy of g(t) is determined based on the data of transient current density Js and dynamical relaxation rate Q by the generalized inversion scheme (GIS), which suggests that both the δ(Tc)- and δ(l)-pinning may be responsible for the vortex dynamical behaviors in CaKFe4As4 under field parallel to c-axis (H // c). The value of Js for field parallel to ab-plane (H // ab) is obviously larger than that of H // c, this indicates that the flux pinning mechanisms are distinct in different crystal orientations. Under H // ab, a dip structure in the magnetic hysteresis loops (MHLs) is obtained around zero field, which is ascribed to planar defects in ab-plane. We further analyze the flux pinning mechanisms and find that the abnormal flux pinning behaviors should originate from its unique structure in CaKFe4As4.

Ba0.5Cs0.5Fe2As2 films on BaFe2As2 substrates with T c ∼ 29.8 K have been synthesized by a simple one-step self-flux method. Quasi-single-crystal Ba0.5Cs0.5Fe2As2 films are more favorable in 122-type crystal structure but not in 1144-type. Based on the obtained Ba0.5Cs0.5Fe2As2 films, the temperature and angle-dependent resistivity are measured under a magnetic field up to 9.0 T. The results indicate that the films exhibited high upper critical fields, strong flux pinning potential and low anisotropic factors. By scaling the resistivity within the framework of the anisotropic Ginzburg–Landau (GL) theory, the angle-dependent resistivity of Ba0.5Cs0.5Fe2As2 films under various magnetic fields at a fixed temperature can be scaled to one curve. Both the Werthamer–Helfand–Hohenberg and GL methods give a similar anisotropic factor ∼3.0. Ba0.5Cs0.5Fe2As2, cannot naturally grow bulk single crystals but only form film on the surface of BaFe2As2 crystal under normal pressure. It is reasonable to infer that surface strain should play a key role in the formation of Ba0.5Cs0.5Fe2As2 films. Thus, it is believed that element doping or substitution may be one of the most effective methods to obtain doped-Ba0.5Cs0.5Fe2As2 bulk single crystals.

Using a three-dimensional classical ensemble model, we investigate the dependence of relative frequency and relative initial phase for nonsequential double ionization (NSDI) of atoms driven by orthogonal two-color (OTC) fields. Our findings reveal that the NSDI probability is clearly dependent on the relative initial phase of OTC fields at different relative frequencies. The inversion analysis results indicate that adjusting the relative frequency of OTC fields helps control returning probability and flight time of the first electron. Furthermore, manipulating the relative frequency at the same relative initial phases can vary the revisit time of the recolliding electron, leading that the emission direction of Ar2+ ions is explicitly dependent on the relative frequency.

We propose and theoretically demonstrate a scheme to generate elliptically polarized attosecond pulses with mixed gases. As the harmonic radiations from different gases with opposite orbital parity interfere destructively for one helicity component and constructively for the other, the high-order harmonics from the mixture exhibit large ellipticity with the same helicity in a wide spectral range. Hence, highly elliptically polarized attosecond pulses can be generated from the mixed gases and the ellipticity can be tuned by controlling the mixing ratio and the molecular alignment angle. Furthermore, this interference effect is only related to the features of the mixed gases such as the structure and orbital symmetry of the molecules and atoms. The polarization control is independent of the temporal profile manipulation of the attosecond pulses by shaping the driving field. Consequently, our work paves an effective and convenient way to produce elliptically polarized isolated attosecond pulses with mixed gases by optimizing the polarization and temporal profile individually.

Systematic ac susceptibility measurements have been carried out to study the vortex dynamics in CaKFe

Using a three-dimensional classical ensemble method, we theoretically investigated frustrated double ionization (FDI) of atoms driven by the orthogonal two-color (OTC) laser pulses. The numerical results show that the FDI yields could be controlled by changing the relative phase of the OTC fields. Moreover, the relative contribution of the two pathways of FDI, corresponding to the processes wherein the firstly or the secondly ionized electron is finally recaptured when the laser field is over, could also be manipulated by changing the relative phase of the OTC fields. The underlying dynamics for this relative-phase dependence of the FDI pathways is revealed by back-tracing the classical trajectories of the FDI events. Interestingly, the energy distributions of the highly excited states of the atom ions in the FDI events also display a sensitive relative phase dependence.

The nonsequential double ionization (NSDI) of atom is revisited by elliptically polarized few-cycle laser pulse with the classical ensemble method. We focus on the events that both electrons emit into the same direction along the long and short axis of the laser polarization plane, and how do the correlated electron momentum spectra of these two events depends on the carrier-envelope-phase (CEP). We first exhibit that the double-ionization probability has a negligible dependence on CEP. Back analysis shows that the ionization dynamics of the second electron are strongly depend on the CEP, which is significantly responsible for the CEP-dependent correlated electron momentum spectra. Besides, the correlated electron momentum spectrum along the long axis of the laser polarization plane reproduces the so-called V-like structure (also called the figurelike structure) observed in experiments [A. Staudte, et al., Phys. Rev. Lett. 99, 263002 (2007); A. Rudenko, et al., Phys. Rev. Lett. 99, 263003 (2007)]. We sort the V-like shape into two regions and find that the different regions exhibit significantly different dynamics behaviors. Simultaneously, we demonstrate that the electron pairs emitted into the same direction along the short axis of the laser polarization plane is a result of the nuclear–electron attraction, and both the nuclear–electron attraction and e–e repulsion significantly contribute to the V-like structure.

Systematic ac susceptibility measurements have been carried out to study the vortex dynamics in CaKFe4As4 and Ba0.6K0.4Fe2As2 single crystals under various temperatures, dc magnetic fields, ac field frequencies and amplitudes. The field-temperature phase diagrams were shown, and the characteristics of irreversibility line were also derived. The specific expressions of activation energy on the parameters of temperature (T), current density (J), and dc magnetic field (H) are obtained according to these data. The results indicate that both superconductors have similar functional expressions of activation energy and flux pinning behaviors. Though both CaKFe4As4 and Ba0.6K0.4Fe2As2 superconductors exhibit very strong flux pinning ability, the vortex pinning potential in CaKFe4As4 is slightly smaller than that in Ba0.6K0.4Fe2As2, which may result from its distorted FeAs4-tetrahedron in CaKFe4As4. The depinning critical current densities at the limit of low temperature and low field were also extrapolated, yielding the corresponding values of Jc0(0) ~ 1.0×108 and 2.2×108 A cm-2 for CaKFe4As4 and Ba0.6K0.4Fe2As2 superconductors, respectively, which suggest potential applications.

The aim of the present study was to investigate the function and mechanism of action of microRNA (miRNA or miR)-199a-3p in vascular endothelial cell injury induced by type 2 diabetes mellitus (T2DM). A total of 36 patients with T2DM (26 males and 10 females; mean age, 52.5±7.0 years) and 20 healthy subjects (10 males and 10 females; mean age, 55.6±4.5 years) were included in the present study. Peripheral blood samples were obtained from all participants and total RNA was extracted Reverse transcription-quantitative polymerase chain reaction was performed to determine the expression of miR-199a-3p. Following the transfection of human umbilical vein endothelial cells (HUVECs) with a negative control (NC) miRNA or miR-199a-3p mimics, cell proliferation was assessed using a Cell Counting kit-8 assay. Cell migration was investigated using Transwell assays and flow cytometry was performed to detect the apoptosis of HUVECs. HUVECs were infected with Ad-GFP-LC3B and laser-scanning confocal microscopy was performed to observe autophagosomes in HUVECs. Western blotting was used to measure the expression of proteins associated with autophagy and the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor (NF)-κB signaling pathway. MiR-199a-3p was downregulated in peripheral blood from patients with T2DM compared with healthy subjects. Transfection with miR-199a-3p mimics promoted the proliferation and migration of HUVECs. However, miR-199a-3p overexpression inhibited the apoptosis of HUVECs. MiR-199a-3p facilitated HUVEC autophagy by affecting autophagy-associated signaling pathways. Furthermore, miR-199a-3p regulated the biological functions of HUVECs via the PI3K/AKT/NF-κB signaling pathway. The results of the present study suggest that miR-199a-3p expression was reduced in patients with T2DM compared with healthy subjects and may be associated with vascular endothelial cell injury. In addition, miR-199a-3p promoted the proliferation, migration and autophagy of HUVECs, potentially by regulating the PI3K/AKT/NF-κB signaling pathway. Therefore, miR-199a-3p may function as protector of vascular endothelia.

We have successfully fabricated petal-like Ni3S2 nanosheets on three-dimensional carbon nanotube foams (Ni3S2@3D-CNTF) via a simple one-pot solvothermal method. The 3D-CNTFs were firstly prepared by reducing greenhouse gas of CO2 with an eco-friendly self-assembly technology. The electrochemical performances of obtained Ni3S2@3D-CNTF composite were evaluated as anode materials for Li-ion batteries, which demonstrates a high reversible capacity of 968.2 mAh g−1 at 0.2 A g−1, good rate performance of 524.1 mAh g−1 at 8 A g−1, and long life cycling stability of 93.6% capacity retention after 900 cycles at 4 A g−1. The excellent rate properties and cycling stability can be ascribed to the 3D porous network structure of carbon and abundant active sites of nanosized Ni3S2 sheets. All these superior electrochemical characteristics indicate that the composite of Ni3S2@3D-CNTF can be considered as a competitive participant for high-performing negative electrode materials for Li-ion batteries.

With a fully classical ensemble model, we investigate the nonsequential double ionization (NSDI) of Xe by linearly polarized (LP) and elliptically polarized (EP) ultra-short laser pulses respectively. For these two cases, the momentum distributions of correlated electron in the direction of parallel to the laser field (for LP) and along the long axis of the laser polarization plane (for EP) show significant difference, but along perpendicular to the laser field (for LP) and the short axis of the laser polarization plane (for EP), the momentum distributions often emit into the opposite hemisphere. By back analyzing the classical trajectories of NSDI, it shows that the recollision is still the underlying mechanism. For LP, the recollision often occurs at the first returning of tunneled electron, but for EP, all of the successful NSDI come from the “exit collision” [PRA 81, 023409 (2010)] which is responsible for the momentum distribution of correlated electron. Moreover, for LP, we divide the trajectories of NSDI into four cases based on the time delay between singly ionization and recollision, and find the ionization mechanism is different for them, so the momentum distribution of correlated electron exhibits a strongly distinction.

With the three-dimensional classical ensemble model, we have investigated the complex electron correlations in N 2 double ionization by the mid-infrared laser pulses over a wide range of laser intensities. Our numerical results show that the correlated longitudinal electron momentum spectra exhibit rich correlated patterns with the increase of the laser intensity. At the low and high laser intensities, the correlated electron momentum spectra display an obvious finger-like structure, while at the moderate laser intensity the finger-like structure is not observed and there is a certain contribution from the back-to-back emission. By back-analyzing the classical trajectories, the subcycle dynamics of the molecular double ionization in the long-wavelength regime are revealed and the complex electron correlations are explained.

Using a full-dimensional Monte Carlo classical ensemble method, we present a theoretical study of atomic nonsequential double ionization (NSDI) with mid-infrared laser fields, and compare with results from near-infrared laser fields. Unlike single-electron strong-field processes, double ionization shows complex and unexpected interplays between the returning electron and its parent ion core. As a result of these interplays, NSDI for mid-IR fields is dominated by second-returning electron trajectories, instead of first-returning trajectories for near-IR fields. Some complex NSDI channels commonly happen with near-IR fields, such as the recollision-excitation-with-subsequent-ionization (RESI) channel, are virtually shut down by mid-IR fields. Besides, the final energies of the two electrons can be extremely unequal, leading to novel e-e momentum correlation spectra that can be measured experimentally.

Using a classical ensemble method, we revisit the topic of recollision and nonsequential double ionization with elliptically polarized laser fields. We focus on how the recollision mechanism transitions from short trajectories with linear polarization to long trajectories with elliptical polarization. We propose how this transition can be observed by meansuring the carrier-envelop-phase dependence of the correlated electron momentum spectra using currently available few-cycle laser pulses.

With a classical three-dimensional ensemble model, we investigate the correlation behavior of the electrons from nonsequential double ionization of helium at intensities below the recollision threshold. At these laser intensities well below the recollision threshold, the two-electron momentum spectra pairs along the laser polarization show anticorrelated behaviors. This anticorrelated behavior becomes stronger when the laser intensity decreases, and then becomes weaker as the laser intensity further decreases. The responsible microscopic dynamics for the anticorrelated behavior and its intensity dependence is explored by back analyzing the double ionization trajectories.

The microscopic recollision dynamics in strong-field nonsequential double ionization of Ar atoms is investigated using three-dimensional classical ensembles. By adjusting the nuclear Coulomb potential, we can excellently reproduce the experimental results both within the laser intensity regimes well above the recollision threshold and well below the recollision threshold quantitatively. More importantly, our trajectory analysis clearly reveals the particular electronic dynamics in recollision process: the momentum of the recolliding electron encounters a sudden change both in magnitude and in direction when it approaches the nucleus closely, which show that the nuclear Coulomb attraction plays a key role in the recollision process of nonsequential double ionization of Ar atoms.

We theoretically investigate the generation of ultra broadband supercontinuum from helium atoms exposed to a linearly polarized mid-infrared field. By adopting a UV trigger pulse to the mid-infrared field, the continuous harmonic yields are significantly enhanced by 3.5 orders, and a supercontinuum with the width of 230 eV is observed. The spectrum can support a sub-20 as pulse, which is below one atomic unit of time (24 as). The short quantum path is selected by adjusting the time delay between the UV pulse and the mid-infrared pulse, then broadband single 70 as pulses with tunable central wavelengths are obtained, which can be extended to the ‘water window’ region (284–543 eV).

We have investigated the recollision dynamics of correlated electron from nonsequential double ionization (NSDI) with 3200 nm laser fields at a wide range of intensities using a full-dimensional classical ensemble method. The numerical results show that for the mid-infrared laser fields, the double ionization probability versus laser peak intensity still displays a much clear “traditional” knee structure representing NSDI. At low intensity, the electron momentum correlated spectrum along the laser polarization direction shows a V-shaped structure; whereas at high intensity, the spectrum exhibits a clearly cross-shaped structure. We demonstrate that both the V-shaped structure and the cross-shaped structure are the results of extremely asymmetric energy sharing of the two electrons at recollision. Moreover, the most prominent contribution to NSDI is from the second-returning trajectory and the first-returning trajectory is significantly suppressed. What’s more, the mechanism of NSDI is from recollision impact ionization (RII) channel as well as recollision-excitation-with-subsequent-ionization (RESI) channel. We find that at low intensity, only the RII channel contributes to V-shaped structure; whereas at high intensity, both the RII and RESI channels have comparable contribution to the cross-shaped structure. Further, we diagnose the recolliding electron and the bound electron separately by tracing the classical trajectories.

First-principles calculations of the lattice parameter, electron density maps, density of states and elastic constants of Mg2Si are reported. The lattice parameter is found to differ by less than 0.8% from the experimental data. Calculations of density of states and electron density maps are also performed to describe the orbital mixing and the nature of chemical bonding. Our results indicate that the bonding interactions in the Mg2Si crystal are more covalent than ionic. The quasi-harmonic Debye model, by means of total energy versus volume calculations obtained with the plane-wave pseudopotential method, is applied to study the elastic, thermal and vibrational effects. The variations of bulk modulus, Gruneisen parameter, Debye temperature, heat capacity Cv, Cp and entropy with pressure P up to 7 GPa in the temperature interval 0–1300 K have been systemically investigated. Significant differences in properties are observed at high pressure and high temperature. When T

To investigate the different effect of three methods of blood purification for paraquat poisoning patients:hemoperfusion (HP), hemoperfusion combined with hemodialysis (HP + HD), hemoperfusion combined with continuous veno-venous hemofiltration (HP + CVVH).72 cases of paraquat poisoning patients were divided into three groups after giving conventional therapy HP group, HP + HD group, HP + CVVH group. Compared the rate of decline concentrations of paraquat in blood, the liver and the kidney damage between before and after blood purification and contrast the mortality in three groups after different method of blood purification.The rate of decline concentrations of paraquat in blood of the HP + HD group and HP + CVVH group were both significantly greater than the HP group, but this result of HP + HD group has no significant difference compared with HP + CVVH group; Among the three groups of patients after 72 hours, the degree of dysfunction of liver of the HP + HD group and HP + CVVH group were both significantly lower than the HP group, whilely the degree of dysfunction of kidney of the HP + HD group was significantly lower than the HP group and the HP + CVVH group. The survival time of the HP + HD group and the HP + CVVH group were significant linger than the HP group, but the comparison among the three groups had no significant difference in mortality.Three blood purification methods can effectively remove paraquat absorbed into the blood, and the hemoperfusion combined with hemodialysis or continuous veno-venous hemofiltration can effectively reduce the degree of damage of liver and kidney and also can prolong survival time, but did not significantly improve the survival rate of patients.

The carrier-envelope-phase (CEP) dependence of correlated electron dynamics in molecular nonsequential double ionization by few-cycle laser pulses is investigated with the three-dimensional classical ensemble model. Our results show that the asymmetric longitudinal momentum spectra of the doubly charged ions strongly depend on the CEP of the laser pulses, and the CEP-dependent asymmetry in the ions' momentum spectra varies with varying internuclear distance. By tracing the classical trajectories, it is found that the ionization dynamics of the first electron greatly affects the asymmetry. Back analysis reveals that with increasing internuclear distance, the pathway responsible for energy transfer between the two electrons changes from the recollision process to the collision process. This change causes the shape of the CEP-averaged ion momentum distribution to show a double-single-triple peak structure as the internuclear distance increases.

The multielectron dynamics in nonsequential triple ionization (NSTI) of neon atoms driven by mid-infrared (MIR) laser pulses is investigated with the three-dimensional classical ensemble model. In consistent with the experimental result, our numerical result shows that in the MIR regime, the triply charged ion longitudinal momentum spectrum exhibits a pronounced double-hump structure at low laser intensity. Back analysis reveals that as the intensity increases, the responsible triple ionization channels transform from direct (e, 3e) channel to the various mixed channels. This transformation of the NSTI channels leads to the results that the shape of ion momentum spectra becomes narrow and the distinct maxima shift towards low momenta with the increase of the laser intensity. By tracing the triply ionized trajectories, the various ionization channels at different laser intensities are clearly identified and these results provide an insight into the complex dynamics of the correlated three electrons in NSTI.

(Li1−x Fe x OH)FeSe single crystals have been successfully synthesized by a hydrothermal ion-exchange technique. We have carried out systematic research on the influence of the concentration of selenourea (c m) on the superconducting properties of (Li1−x Fe x OH)FeSe single crystals. The optimized specimens possess an onset superconducting transition temperature T c of up to 42 K obtained at c m = 0.8 mol l−1, and the corresponding residual resistivity ratio (RRR = ρ (300 K)/ρ (T c)) is estimated to be 11. The vortex liquid-to-glass phase transition has been discussed based on the collective pinning model. The large distance between the H g and H c2 lines, as well as the much narrower region of the pinned vortex-liquid phase, indicate a weak vortex-pinning ability in (Li1−x Fe x OH)FeSe single crystals. The big out-plane anisotropy behavior versus temperature has been explored according to the anisotropic Ginzburg–Landau theory, and the anisotropy factor Γ displays linear behavior towards temperature similar to that of SmFeAsO1−x F x superconductors.

Large size single crystals of (Li1−x Fe x )OHFeSe have been synthesized via a hydrothermal ion-exchange technique using K0.8Fe2Se2 single crystals as the main raw material. The onset superconducting transition temperature is up to 40.3 K. The critical current density is as large as 1.9 × 105 A cm−2 at 5 K and self field. The upper critical fields have been determined by analyzing the relationship between resistivity and temperature under different applied fields along c-axis and ab-plane, respectively. An anisotropic factor about 11 is obtained, which is further confirmed by fitting the data obtained from the angle-dependent resistivity according to the anisotropic Ginzburg–Landau theory. The flux pinning potential (U 0/k B) is as large as 6429 and 3115 K at 0.1 T in H//ab and H//c orientation, respectively. However, the flux pinning potentials are very sensitive to the applied magnetic field and will fast decrease with increase of the magnetic field in both directions, which are obviously different from the Ba1−x K x Fe2As2 superconductor indicating a different flux pinning mechanism in the two kinds of superconductors.

The surface diffraction gratings on lithium niobate single crystal ablated by a femtosecond laser pulse at a wavelength of 800 nm have been investigated. The diffraction efficiencies of the gratings ablated with various parameters were measured by He-Ne laser at a wavelength of 632.8 nm. The 1-order diffraction efficiencies of the gratings improve from 1.7% to 2.3% with the increase of ablation speed from 20μm/s to 200μm/s, and decrease from 1.9% to 1.3% with the increase of pulse energy from 70nJ to 110nJ, respectively. The experimental and theoretical results show that the diffraction efficiencies of gratings can be improved by increase of ablation speed and grating constant or decrease of pulse energy.

With the fully classical ensemble model, we investigate the correlated electron dynamics of nonsequential double ionization (NSDI) by few-cycle laser pulses at 3T (T is the laser cycle) and compared it with the 6T case. For the 6T laser pulse, the momentum distribution of correlated electron in the direction parallel to the laser polarization exhibits a V-like structure which has been observed in the experiment. [Camus et al., Phys. Rev. Lett. 108, 073003 (2012)]. However, for the 3T laser pulse, the momentum distribution shows a surprising arc-like structure. Meanwhile, the correlated electron momentum spectrum in the direction perpendicular to the laser polarization shows a more stronger anticorrelated behavior for the 3T laser pulse than that of the 6T laser pulse. By analyzing all the classical trajectories of NSDI, for the 3T laser pulse, the contribution to NSDI only comes from the first return and the latter returns are completely supressed, which is different from the case of the 6T laser pulse where not only the first return but also the latter returns contribute to the NSDI events. Moreover, the recolliding energies are often higher for the 3T laser pulse than that of the 6T laser pulse due to a more rapid turn on of laser field for the 3T laser pulse which plays a key role for the arc-like structure. The more energetic recollisions that occur in the 3T laser pulse lead to greater anticorrelation in the transverse momenta than is observed in the 6T laser pulse with less energetic recollisions.

We investigated the nonsequential double ionization (NSDI) of Xe by linearly polarized (LP) and elliptically polarized (EP) laser pulses using the classical ensemble model. For the two cases, the ensemble from NSDI was separated into two kinds of subensemble according to the relative momentum along the y-axis [Formula: see text], respectively. The results show only for the case of relatively small [Formula: see text], the momentum distribution along the x-axis can show a V-like shape obviously, which is according with the experiment [Phys. Rev. Lett.99, 263003 (2007)]. What is important is that we firstly examine the role of the repulsion interaction between two electrons for the two kinds of subensemble, and find that the process of NSDI for the case of relatively small [Formula: see text] exits a strong repulsion interaction which contributes significantly to the V-like shape. However, for the case of relatively big [Formula: see text], the repulsion interaction between two electrons is relatively weak, and both the nuclear Coulomb attraction and electric field force dominate the process of NSDI.

Using a classical ensemble model, we investigate the correlation behaviour of electrons originating from nonsequential double ionization (NSDI) of argon atoms by the elliptically polarized laser pulses. Because of the ellipticity, not only the first electron to return but also the later return of tunneled electrons contribute significantly to NSDI. We mainly discuss two kinds of events of NSDI originating from the first and the second return separately. For the NSDI resulting from the recollision of the first return, the correlated electron momentum spectrum along the long axis of the laser polarization plane reveals an obvious V-like shape, located at the first and third quadrant. However, for the NSDI resulting from the recollision of the second return, the momenta of two electrons are distributed in the four quadrants uniformly. By analysing the trajectories of these two kinds, we find that the recollision energy and the laser phase at recollision are different for the first and second returning trajectories, which are responsible for the difference in the correlated behavior of the final electron momentum.

The electron dynamics in strong field nonsequential double ionization (NSDI) of nitrogen molecules by mid-infrared (MIR) laser pulses is investigated with the three-dimensional classical ensemble model. The numerical results show that in the MIR regime, the correlated behavior of the two electrons from NSDI is independent on the molecular alignment, contrary to the case in the near-infrared (NIR) regime where the electron correlations exhibit a strong alignment dependence. In consistent with the experimental results, our numerical results show that the longitudinal momentum spectrum of the doubly charged ion evolves from a wide single-hump structure at NIR regime into a double-hump structure when wavelength enters the MIR regime. This double-hump structure becomes more pronounced as the wavelength further increases. The responsible microscopic electron dynamics of NSDI at the MIR regime is explored by back analysis of the classical trajectories.

With the classical fermion molecular dynamics model (FMD), we investigated electron emissions from H(2)(+) by circularly polarized laser pulses. The obtained electron momentum distribution clearly shows an angular shift relative to the expected direction for H(2)(+) aligned parallel to the polarization plane, which is in good agreement with the recent experimental result. By tracing the classical trajectory, we provide direct evidence for the electron delayed emission with respect to the instant when the electric field is parallel to the molecular axis, which was regarded as the origin of the angular shift in the electron momentum distribution. Furthermore, we find that the angular shift decreases with increasing the laser wavelength.