Covariance Mapping Studies of 7-Azaindole Fragments

Extreme multielectron ionization of elemental clusters in ultraintense laser fields

“…We advanced 29,37,65 an MD simulation scheme for the high‐energy electron dynamics and nuclear dynamics in a cluster interacting with an ultraintense laser field (I M = 10 15 ‐10 20 W cm −2 ). This scheme incorporated the coupling with the laser field, inner field effects of electrons and ions, screening and ionic fields by the electrons, and reactive EII.…”

“…This scheme incorporated the coupling with the laser field, inner field effects of electrons and ions, screening and ionic fields by the electrons, and reactive EII. This scheme also includes magnetic field and relativistic effects, which are important in the highest intensity domain of I M = 10 18 ‐10 20 W cm −2 . The laser electric field acting on the elemental or molecular cluster was taken as F ℓ (t) = F ℓ0 (t)cos(2πvt), where v is the laser frequency and F ℓ0 (t) is the pulse envelope function.…”

“…The cluster response to ultraintense laser fields triggers well‐characterized ultrafast electron dynamics (on the time‐scale of <1–100 fs). The response of clusters to ultraintense laser fields (I = 10 15 –10 20 W cm −2 ) is distinct both from the electron dynamic response in ordinary fields (I ≾ 10 13 W cm −2 ), where perturbative quantum electrodynamics is applicable, and from the response of “small” atoms or molecules to ultraintense laser fields, which is triggered by the barrier suppression single‐step ionization mechanism. When the cluster size (or the size of a large chemical system) significantly exceeds the size of the constituent barrier distance, a well‐characterized compound cluster ionization mechanism is manifested.…”

“…For higher intensities of I M = 10 18 W cm −2 and I M = 10 19 W cm −2 , the electron angular distribution is spatially anisotropic, assuming a “sausage type” structure along the laser electric field direction. Attosecond‐femtosecond response of the nanoplasma. At the intensities of I M = 10 18 ‐10 19 W cm −2 the “sausage type” structure of the electron cloud oscillates along the electric field direction on the timescale v −1 of the laser period, manifesting ultra‐fast electron dynamics. The outer ionization of the nanoplasma can be either partial (at intensities of 10 15 ‐10 16 W cm −2 ) or complete (at highest intensities of 10 18 ‐10 20 W cm −2 ). Persistent and transient nanoplasmas. At intensities of I M = 10 15 ‐10 16 W cm −2 , where outer ionization is partial, a persistent nanoplasma on the timescale of t‐t s > 100 fs exists, while for higher intensities of I M = 10 18 ‐10 19 W cm −2 , a transient nanoplasma is formed, being completely depleted on the timescale of t‐t s ⋍ 15‐25 fs. Sequential‐parallel multielectron inner ionization, nanoplasma formation, and outer ionization are exhibited. Coulomb explosion, which is discussed elsewhere, occurs parallel and sequential with outer ionization.…”

“… Abstract In this paper we present computational and theoretical studies of extreme multielectron ionization in Xe n clusters (n = 55‐2171, initial cluster radii R 0 = 8.7‐31.0 Å) driven by ultraintense Gaussian infrared laser fields (peak intensity I M = 10 15 ‐10 20 W cm −2 , temporal pulse length τ = 10‐100 fs, and frequency v = 0.35fs −1 ). The microscopic approach, which rests on three sequential‐parallel processes of inner ionization, nanoplasma formation, and outer ionization, properly describes the high ionization levels (with the formation of {Xe q+ } n with q = 5‐36), the inner/outer cluster ionization mechanisms, and the nanoplasma response.…”