Displacement effect in strong-field atomic ionization by an XUV pulse

We study strong-field atomic ionization driven by an XUV pulse with a non\-zero displacement, the quantity defined as the integral of the pulse vector potential taken over the pulse duration. We demonstrate that the use of such pulses may lead to an extreme sensitivity of the ionization process to subtle changes of the parameters of a driving XUV pulse, in particular, the ramp-on/off profile and the carrier envelope phase. We illustrate this sensitivity for atomic hydrogen and lithium driven by few-femto\-second XUV pulses with intensity in the $\rm 10^{14}~W/cm^2$ range. We argue that the observed effect is general and should modify strong-field ionization of any atom, provided the ionization rate is sufficiently high.Comment: 5 pages, 7 figure

Pulse-Shape Effects On The Autler-Townes Doublet In Strong-Field Ionization Of Atomic Hydrogen

Klaus Bartschat, Alexei Grum-Grzhimailo, MentorsA characteristic feature in strong-field multi-photon ionization processes is the so-called Autler-Townes Doublet [1] that occurs due to the transient splitting of atomic energy levels in the electric field of the laser pulse. Preliminary studies [2] revealed that the shape of this doublet structure can be strongly dependent on the details of the pulse structure. This dependence is not only surprising, but may also be a limiting factor on the ability of calibrating absolute laser intensities [3]. [1] S. H. Autler and C. H. Townes, Phys. Rev. 100 (1955) 703. [2] A. N. Grum-Grzhimailo, M. N. Khaerdinov, and K. Bartschat, Phys. Rev. A 88 (2013) 055401. [3] M. G. Pullen et al., Phys. Rev. A 87 (2013) 053411Drake University, College of Arts & Sciences, Department of Physics and Astronomy; Institute of Nuclear Physics, Moscow State Universit

Conceptualizing gratitude and appreciation as a unitary personality trait

Gratitude and appreciation are currently measured using three self-report instruments, the GQ6 (1 scale), the Appreciation Scale (8 scales), and the GRAT (3 scales). Two studies were conducted to test how these three instruments are interrelated, whether they exist under the same higher order factor or factors, and whether gratitude and appreciation is a single or multi-factorial construct. In Study 1 (N = 206) all 12 scales were subjected to an exploratory factor analysis. Both parallel analysis and the minimum average partial method indicated a clear one-factor solution. In Study 2 (N = 389) multigroup confirmatory factor analysis supported the one-factor structure, demonstrated the invariance of this structure across gender, and ruled out the confounding effect of socially desirable responding. We conclude gratitude and appreciation are a single-factor personality trait. We suggest integration of gratitude and appreciation literatures and provide a clearer conceptualization of gratitude

Measurements of the vertical profile, diurnal variation, and secular change of ClO in the stratosphere over Thule, Greenland, February-March, 1992

We report observations of stratospheric chlorine monoxide over the altitude range approx. 16 to 50 km at Thule, Greenland from Feb. 8 to Mar. 24, 1992. A new, more sensitive ground-based mm-wave spectrometer was employed for these measurements, similar in principle to that used earlier for the discovery of low altitude ClO in the Antarctic springtime. In this report, we discuss different aspects of vertical distribution, secular trends, and diurnal variation of ClO in the Arctic stratosphere, based on a preliminary analysis of our Thule data. We see no evidence for large (approx. 1.2-1.5 ppb) amounts of ClO in the lower stratosphere at any time during February or March, in agreement with UARS-MLS findings for this period, and in marked contrast to findings reported for the Arctic in January. We have some evidence for small enhancements (approx. 0.2-0.5 ppb) in the 18-30 km range in late February-early March, which might be associated with volcanic aerosol, rather than PSC, processing

Observed changes in the vertical profile of stratopheric nitrous oxide at Thule, Greenland, February - March 1992

Using a ground-based mm-wave spectrometer, we have observed stratospheric N2O over Thule, Greenland (76.3 N, 68.4 W) during late February and March, 1992. Vertical profiles of mixing ratio ranging from 16 to 50 km were recovered from molecular emission spectra. The profiles of early March show an abrupt increase in the lower-stratosphere N2O mixing ratio similar to the spring-to-summer change associated with the break up of the Antarctic polar vortex. This increase is correlated with changes in potential vorticity, air temperature, and ozone mixing ratio