نتایج جستجو برای: ionization effects

تعداد نتایج: 1578400  

Journal: :Analytical chemistry 2004
Jamie E Elsila Nathalie P de Leon Richard N Zare

Microprobe laser desorption/laser ionization mass spectrometry (microL(2)MS) is a sensitive and selective technique that has proven useful in the qualitative and semiquantitative detection of trace organic compounds, particularly polycyclic aromatic hydrocarbons (PAHs). Recent efforts have focused on developing microL(2)MS as a quantitative method, often by measuring the ratio of signal strengt...

2005
Gregory Lapicki

While fits to 90% of all ever measured K-shell ionization cross sections by protons are on the average within 10% of the ECPSSR [W. Brandt, G. Lapicki, Phys. Rev. A 23 (1981) 1717], this theory systematically overestimates the remaining 10% of all data (comprised mainly of the measurements on heavy target elements) in the slow collision regime of proton velocities less than 0.1 of the orbital v...

2013
Peter F. Lang Barry C. Smith

We have previously used simple empirical equations to reproduce the literature values of the ionization energies of isoelectronic sequences of up to four electrons which gave very good agreement. We reproduce here a kinetic energy expression with corrections for relativity and Lamb shift effects which give excellent agreement with the literature values. These equations become more complex as th...

Journal: :Medical physics 2004
Hugo Bouchard Jan Seuntjens

The present paper addresses reference dose measurements using thimble ionization chambers for quality assurance in IMRT fields. In these radiation fields, detector fluence perturbation effects invalidate the application of open-field dosimetry protocol data for the derivation of absorbed dose to water from ionization chamber measurements. We define a correction factor C(Q)IMRT to correct the ab...

2016
M. R. MILLER A. JAROŃ-BECKER

In this review, we briefly summarize more than a decade of experimental and theoretical investigations regarding the nonadiabatic electron response to intense femtosecond duration laser fields in a variety of molecular systems. Historically, experimental signatures of nonadiabaticity have emerged readily in large, conjugated, or multi-electron systems, disrupting fragmentation behavior and modu...

Journal: :The Journal of chemical physics 2011
Pavla Svrčková Aleš Vítek František Karlický Ivana Paidarová René Kalus

Temperature dependence of vertical ionization energies is modeled for small argon clusters (N ≤ 13) using classical parallel-tempering Monte Carlo methods and extended interaction models based on the diatomics-in-molecules approach. Quantum effects at the zero temperature are also discussed in terms of zero-point nuclear vibrations, either at the harmonic approximation level or at the fully anh...

2009
M Michaillat D Rideau F Aniel C Tavernier H Jaouen

High-energy transport properties of charge carriers in ternary random Si1−x−yGexCy alloys are investigated using Full-Band Monte Carlo simulations. Models for scattering mechanisms include phonon scattering, impact ionization and alloy scattering. Phonon scattering rates are wave-vector dependent and calculated consistently with the Full-Band structure. Impact ionization rates are modeled using...

2003
M. S. Tillack D. Blair S. S. Harilal

Ablation plumes caused by short-pulse laser irradiation provide conditions which are well suited to the formation of nanoclusters. The high saturation ratios and presence of ionization lead to extraordinarily high nucleation rates and small critical radii. We have explored the homogeneous nucleation and heterogeneous growth of condensate from Si targets expanding into a low-pressure He ambient ...

Journal: :The Journal of chemical physics 2009
Adrian Stan Nils Erik Dahlen Robert van Leeuwen

We perform GW calculations on atoms and diatomic molecules at different levels of self-consistency and investigate the effects of self-consistency on total energies, ionization potentials, and particle number conservation. We further propose a partially self-consistent GW scheme in which we keep the correlation part of the self-energy fixed within the self-consistency cycle. This approximation ...

2011
C. Barbieri M. Degroote

The accuracy of the Faddeev random phase approximation (FRPA) method is tested by evaluating total and ionization energies in the basis-set limit. A set of light atoms up to Ar is considered. Comparisons are made with the results of coupled-cluster singles and doubles (CCSD), with third-order algebraic diagrammatic construction [ADC(3)], and with the experiment. It is seen that even for two-ele...

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