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We show that matter-wave diffraction off a single standing laser wave can be used as an accurate measurement scheme for photophysical molecular parameters. These include state-dependent optical polarizabilities and photon-absorption cross…

We carry out a study of the hardness of the radiation of ionizing clusters in HII regions. Firstly, we explore the applicability of the softness parameter, originally defined in the optical for pairs of consecutive ionization stages of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Enrique Perez-Montero , Jose M. Vilchez

The absolute photodetachment cross section of OH- anions at a rotational and translational temperature of 170K is determined by measuring the detachment-induced decay rate of the anions in a multipole radio-frequency ion trap. In comparison…

Atomic Physics · Physics 2009-11-13 S. Trippel , J. Mikosch , R. Berhane , R. Otto , M. Weidemüller , R. Wester

Close-in hot Jupiters are exposed to a tremendous photon flux that ionizes the neutral escaping material from the planet leaving an observable imprint that makes them an interesting laboratory for testing theoretical models. In this work we…

Earth and Planetary Astrophysics · Physics 2016-02-17 E. M. Schneiter , A. Esquivel , C. S. Villarreal D'Angelo , P. F. Velazquez , A. C. Raga , A. Costa

We examine the impact of helium reionization on the structure of the intergalactic medium (IGM). We model the reionization using a radiative transfer (RT) code coupled to the combined gravity hydrodynamics code Enzo. Neutral hydrogen and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 A. Meiksin , E. R. Tittley

We use a combination of analytic and numerical arguments to consider the impact of quasar photo-heating during HeII reionisation on the thermal evolution of the intergalactic medium (IGM). We demonstrate that rapid (\Delta z< 0.1-0.2),…

Astrophysics · Physics 2009-11-13 James S. Bolton , S. Peng Oh , Steven R. Furlanetto

The energy levels of hydrogen and helium atoms in strong magnetic fields are calculated in this study. The current work contains estimates of the binding energies of the first few low-lying states of these systems that are improvements upon…

Astrophysics · Physics 2012-02-08 Anand Thirumalai , Jeremy S. Heyl

We investigate the importance of ambipolar diffusion and Hall currents for high-resolution comprehensive ('realistic') photospheric simulations. To do so we extended the radiative magnetohydrodynamics code \emph{MURaM} to use the…

Solar and Stellar Astrophysics · Physics 2015-06-04 Mark C. M. Cheung , Robert H. Cameron

Advanced techniques for manipulation of internal states, standard in atomic physics, are demonstrated for a charged molecular species for the first time. We address individual hyperfine states of ro-vibrational levels of a diatomic ion by…

Atomic Physics · Physics 2015-05-08 U. Bressel , A. Borodin , J. Shen , M. Hansen , I. Ernsting , S. Schiller

We present a time-dependent localized Hartree-Fock density-functional linear response approach for the treatment of photoionization of atomic systems. This approach employs a spin-dependent localized Hartree-Fock (SLHF) exchange potential…

Quantum Physics · Physics 2015-05-13 Zhongyuan Zhou , Shih-I Chu

The polarization operator in a constant and homogeneous magnetic field of arbitrary strength is investigated on mass shell. The calculations are carried out at all photon energies higher the pair creation threshold as well as lower this…

High Energy Physics - Theory · Physics 2014-11-11 V. M. Katkov

Photo-electric absorption of blackbody photons is an important process which limits the acceleration of ions under the space-charge limited flow boundary condition at the polar caps of pulsars with positive corotational charge density.…

High Energy Astrophysical Phenomena · Physics 2015-05-30 P. B. Jones

The hydrogen envelope is the outermost layer of a DA white dwarf; it makes up the entirety of the stellar photosphere, and yet its typical extent is difficult to model theoretically and remains poorly observationally constrained. As a…

Solar and Stellar Astrophysics · Physics 2026-03-05 Stefan M. Arseneau , J. J. Hermes , Maria E. Camisassa , Roberto Raddi , Evan B. Bauer

The photodesorption of icy grain mantles has been claimed to be responsible for the abundance of gas-phase molecules toward cold regions. Being water a ubiquitous molecule, it is crucial to understand its role in photochemistry and its…

Instrumentation and Methods for Astrophysics · Physics 2017-12-27 Gustavo A. Cruz-Diaz , Rafael Martín-Doménech , Elena Moreno , Guillermo M. Muñoz Caro , Yu-Jung Chen

We study the interconnection between the results of two qualitatively different approximate calculations of photoionization cross sections, $\sigma_{n\ell}$, for neutral atoms ($A$) or their cations ($A^+$), centrally confined inside a…

Atomic Physics · Physics 2024-09-19 V. K. Dolmatov , L. V. Chernysheva , V. G. Yarzhemsky

We have studied the radiative decay of the 2s state of one-electron and one-muon ions, where the two-photon mechanism plays an important role. Due to the nuclear size corrections the radiative decay of the 2s state in the electron and muon…

Atomic Physics · Physics 2022-07-27 V. A. Knyazeva , K. N. Lyashchenko , M. Zhang , D. Yu , O. Yu. Andreev

In a recent publication [arXiv:2010.14579], we introduced a new type of atomic magnetometer, which relies on hydrohalide photo-dissociation to create high-density spin-polarized hydrogen. Here, we extend our previous work and present a…

The pulsed-field-ionization zero-kinetic-energy photoelectron spectrum of H$_2$ has been recorded in the vicinity of the dissociative-ionization threshold following three-photon excitation via selected rotational levels of the B…

Chemical Physics · Physics 2017-01-04 Maximilian Beyer , Frédéric Merkt

The widely accepted assumption is that metals detected in the spectra of a few cool helium-rich white dwarfs cannot be of primordial origin and therefore must be accreted from the interstellar medium. However, the observed abundances of…

Astrophysics · Physics 2007-05-23 Susanne Friedrich , Stefan Jordan , Detlev Koester

In recent years a number of white dwarfs has been observed with very high surface magnetic fields. We can expect that the magnetic field in the core of these stars would be much higher (~ 10^{14} G). In this paper, we analytically study the…

Solar and Stellar Astrophysics · Physics 2012-05-09 Aritra Kundu , Banibrata Mukhopadhyay
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