Abstract:We have studied highly excited autoionizing states in atomic sodium, using two laser beams and synchrotron radiation. We have observed the electron spectra resulting from the decay of these 2p 5 3s4p, 2p 5 3s4d, and 2p 5 3s5s states to the 2p 6 l So ground state of Na + . The excitation energies and the relative oscillator strengths of inner-shell transitions in the excited atoms have been measured.PACS numbers: 32.80.Fb, 32.80.Dz, 32.80.Hd, 32.80.Wr In this Letter, we present the first experimental evidenc… Show more
“…This is also the origin of the quadratic pressure dependence of the high harmonic signals, as well as their unusual strengths, that had been found in the very first experimental observations (e.g. [38,39]). …”
Section: Dipole Expectation Valuesupporting
confidence: 55%
“…Both the experimental and the theoretical spectra in Fig. 13 show the Ramanallowed series II: (10 , 18 , 26 , 34 , 42 , ..) Bc, but not the series I: (6,14,22,30,38, ..) Bc, seen for N 2 . The anomalous series III: (20, 28, 36, 44,..)…”
Section: E Signals In the Frequency Domainmentioning
A theory of ultra-fast pump-probe experiments proposed by us earlier [F.H.M. Faisal et al., Phys. Rev. Lett. 98, 143001 (2007) and A. Abdurrouf, Phys. Rev. Lett. 100, 123005 (2008)] is developed here fully and applied to investigate the phenomena of dynamic alignment and high harmonic generation (HHG) from coherently rotating linear molecules. The theory provides essentially analytical results for the signals that allow us to investigate the simultaneous dependence of the HHG signals on the two externally available control parameters, namely, the relative angle between the polarizations, and the delay-time between the two pulses. It is applied to investigate the characteristics of high harmonic emission from nitrogen and oxygen molecules that have been observed experimentally in a number of laboratories. The results obtained both in the time-domain and in the frequency-domain are compared diwith the observed characteristics as well as directly with the data and are found to agree remarkably well. In addition we have predicted the existence of a "magic" polarization angle at which all modulations of the harmonic emission from nitrogen molecule changes to a steady emission at the harmonic frequency. Among other things we have also shown a correlation between the existence of the "magic" or critical polarization angles and the symmetry of the active molecular orbitals, that is deemed to be useful in connection with the "inverse problem" of molecular imaging from the HHG data.
“…This is also the origin of the quadratic pressure dependence of the high harmonic signals, as well as their unusual strengths, that had been found in the very first experimental observations (e.g. [38,39]). …”
Section: Dipole Expectation Valuesupporting
confidence: 55%
“…Both the experimental and the theoretical spectra in Fig. 13 show the Ramanallowed series II: (10 , 18 , 26 , 34 , 42 , ..) Bc, but not the series I: (6,14,22,30,38, ..) Bc, seen for N 2 . The anomalous series III: (20, 28, 36, 44,..)…”
Section: E Signals In the Frequency Domainmentioning
A theory of ultra-fast pump-probe experiments proposed by us earlier [F.H.M. Faisal et al., Phys. Rev. Lett. 98, 143001 (2007) and A. Abdurrouf, Phys. Rev. Lett. 100, 123005 (2008)] is developed here fully and applied to investigate the phenomena of dynamic alignment and high harmonic generation (HHG) from coherently rotating linear molecules. The theory provides essentially analytical results for the signals that allow us to investigate the simultaneous dependence of the HHG signals on the two externally available control parameters, namely, the relative angle between the polarizations, and the delay-time between the two pulses. It is applied to investigate the characteristics of high harmonic emission from nitrogen and oxygen molecules that have been observed experimentally in a number of laboratories. The results obtained both in the time-domain and in the frequency-domain are compared diwith the observed characteristics as well as directly with the data and are found to agree remarkably well. In addition we have predicted the existence of a "magic" polarization angle at which all modulations of the harmonic emission from nitrogen molecule changes to a steady emission at the harmonic frequency. Among other things we have also shown a correlation between the existence of the "magic" or critical polarization angles and the symmetry of the active molecular orbitals, that is deemed to be useful in connection with the "inverse problem" of molecular imaging from the HHG data.
“…These modifications are sizable and can modify dramatically the interaction of the atomic system with soft or hard x-rays. For example the binding energy of the 2p electron varies from 38 eV for a ground state Na atom to 44.9 eV when the outer electron is promoted to 5s using two dye lasers [129][130][131]. This represents an energy shift of 6.9 eV for the 2p core level, a shift that is much larger than the corresponding shifts due to the laser-induced Stark effect for the 2p electron at the laser power of interest here (~10 14 W/cm 2 ).…”
Section: Bound State Structure and Modification Of X-ray Absorptionmentioning
“…A few examples are photon-ion interactions, in which either the ion beam after the collision 2], or electrons emitted are detected; these ions can be highly charged. Other examples are coincidence experiments [3], where low collection efficiencies require intense photonbeams;experiments withactinide targets, wherematerial iseither scarce orhighlyradioactive; and laser-excited targets [4]. Many otherapplications inatomicphysics have been considered [5].…”
Section: Atomic Physics and Highly Charged Ionsmentioning
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