MEASUREMENT AND CALCULATION OF ABSOLUTE SINGLE AND MULTIPLE CHARGE EXCHANGE CROSS SECTIONS FOR Fe {sup q} {sup +} IONS IMPACTING H{sub 2}O
- Atomic and Molecular Physics Group, Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109 (United States)
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States)
- Department of Physics and Astronomy, Pomona College, Claremont, CA 91711 (United States)
- Physics Department, Queen's University, Belfast BT7 1NN (United Kingdom)
- Department of Chemistry, California Institute of Technology, Pasadena, CA 91125 (United States)
- Physics Department, Indiana Wesleyan University, Marion, IN 46953 (United States)
Charge exchange (CE) plays a fundamental role in the collisions of solar- and stellar-wind ions with lunar and planetary exospheres, comets, and circumstellar clouds. Reported herein are absolute cross sections for single, double, triple, and quadruple CE of Fe {sup q} {sup +} (q = 5-13) ions with H{sub 2}O at a collision energy of 7q keV. One measured value of the pentuple CE is also given for Fe {sup 9} {sup +} ions. An electron cyclotron resonance ion source is used to provide currents of the highly charged Fe ions. Absolute data are derived from knowledge of the target gas pressure, target path length, and incident and charge-exchanged ion currents. Experimental cross sections are compared with new results of the n-electron classical trajectory Monte Carlo approximation. The radiative and non-radiative cascades following electron transfers are approximated using scaled hydrogenic transition probabilities and scaled Auger rates. Also given are estimates of cross sections for single capture, and multiple capture followed by autoionization, as derived from the extended overbarrier model. These estimates are based on new theoretical calculations of the vertical ionization potentials of H{sub 2}O up to H{sub 2}O{sup 10+}.
- OSTI ID:
- 21476716
- Journal Information:
- Astrophysical Journal, Vol. 722, Issue 1; Other Information: DOI: 10.1088/0004-637X/722/1/435; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTROPHYSICS
CHARGE EXCHANGE
COMETS
CROSS SECTIONS
ELECTRON TRANSFER
IONIZATION POTENTIAL
IRON IONS
MONTE CARLO METHOD
MULTICHARGED IONS
SOLAR WIND
CALCULATION METHODS
CHARGED PARTICLES
IONS
PHYSICS
SOLAR ACTIVITY
STELLAR ACTIVITY
STELLAR WINDS