ترغب بنشر مسار تعليمي؟ اضغط هنا

Multiple Ionization under Strong XUV to X-ray Radiation

124   0   0.0 ( 0 )
 نشر من قبل Dr. Georgios M. Nikolopoulos
 تاريخ النشر 2014
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

We review the main aspects of multiple photoionization processes in atoms exposed to intense, short wavelength radiation. The main focus is the theoretical framework for the description of such processes as well as the conditions under which direct multiphoton multiple ionization processes can dominate over the sequential ones. We discuss in detail the mechanisms available in different wavelength ranges from the infrared to the hard X-rays. The effect of field fluctuations, present at this stage in all SASE free-electron-laser (FEL) facilities, as well as the effect of the interaction volume integration, are also discussed.



قيم البحث

اقرأ أيضاً

We present a rather elaborate theoretical model describing the dynamics of Neon under radiation of photon energies $sim 93$ eV and pulse duration in the range of 15 fs, within the framework of Lowest non-vanishing Order of Perturbation Theory (LOPT), cast in terms of rate equations. Our model includes sequential as well as direct multiple ionization channels from the 2s and 2p atomic shells, including aspects of fine structure, whereas the stochastic nature of SASE-FEL light pulses is also taken into account. Our predictions for the ionization yields of the different ionic species are in excellent agreement with the related experimental observations at FLASH.
In this work we report the modification of the normal Auger line shape under the action of an intense x-ray radiation. Under strong Rabi-type coupling of the core, the Auger line profile develops into a doublet structure with an energy separation mai nly determined by the relative strength of the Rabi coupling. In addition, we find that the charge resolved ion yields can be controlled by judicious choice of the x-ray frequency.
High harmonic spectra show that laser-induced strong field ionization of water has a significant contribution from an inner-valence orbital. Our experiment uses the ratio of H2O and D2O high harmonic yields to isolate the characteristic nuclear motio n of the molecular ionic states. The nuclear motion initiated via ionization of the highest occupied molecular orbital (HOMO) is small and is expected to lead to similar harmonic yields for the two isotopes. In contrast, ionization of the second least bound orbital (HOMO-1) exhibits itself via a strong bending motion which creates a significant isotope effect. We elaborate on this interpretation by simulating strong field ionization and high harmonic generation from the water isotopes using the time-dependent Schrodinger equation. We expect that this isotope marking scheme for probing excited ionic states in strong field processes can be generalized to other molecules.
59 - A. Nayak , I. Orfanos , I. Makos 2018
We report the observation of multiple ionization of Argon through multi-XUV-photon absorption induced by an unprecedentedly powerful laser driven high-harmonic-generation source. Comparing the measured intensity dependence of the yield of the differe nt Argon charge states with numerical calculations we can infer the different channels -direct and sequential- underlying the interaction. While such studies were feasible so far only with FEL sources, this work connects highly-non-linear-XUV-processes with the ultra-short time scales, inherent to the harmonic pulses, and highlights the advanced perspectives of emerging large scale laser research infrastructures.
A new pathway of strong laser field induced ionization of an atom is identified which is based on recollisions under the tunneling barrier. With an amended strong field approximation, the interference of the direct and the under-the-barrier recollidi ng quantum orbits are shown to induce a measurable shift of the peak of the photoelectron momentum distribution. The scaling of the momentum shift is derived relating the momentum shift to the tunneling delay time according to the Wigner concept. This allows to extend the Wigner concept for the quasistatic tunneling time delay into the nonadiabatic domain. The obtained corrections to photoelectron momentum distributions are also relevant for state-of-the-art accuracy of strong field photoelectron spectrograms in general.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا