Theoretical analysis of the quantum contributions to the reactions molecular hydrogen(v = 1) + atomic hydrogen .fwdarw. atomic hydrogen + molecular hydrogen(v = 0, 1) and molecular hydrogen(v = 1) + atomic deuterium .fwdarw. atomic hydrogen + hydrogen deuteride(v' = 0, 1)

1983 ◽  
Vol 87 (7) ◽  
pp. 1255-1263 ◽  
Author(s):  
Robert B. Walker ◽  
Edward F. Hayes
Keyword(s):  
Theoretical Analysis ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Hydrogen Deuteride

Further investigations of charge exchange and electron detachment - I. Ion energies 3 to 40 keV - II. Ion energies 100 to 4000 eV

1955 ◽  
Vol 227 (1171) ◽  
pp. 466-486 ◽  
Keyword(s):  
Charge Transfer ◽  
Energy Range ◽  
Cross Sections ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Hydrogen Ions ◽  
Electron Detachment ◽  
Rare Gases ◽  
Helium Ions ◽  
Ion Energies

This paper describes the measurement of charge transfer cross-sections for protons, molecular hydrogen ions and helium ions in the rare gases and hydrogen, and electron detachment cross-sections for negative atomic hydrogen ions in the rare gases. Part I describes the energy range 3 to 40 keV. In part II the energy range 100 to 4000 eV is described, and the results are discussed in terms of the pseudo-adiabatic hypothesis. Comparisons are made with other experimental results, and anomalous molecular cases are discussed in terms of reactions involving anti-bonding states.

Formation of metastable atomic hydrogen in the 2sstate from symmetry-resolved doubly excited states of molecular hydrogen

2011 ◽  
Vol 84 (5) ◽  
Author(s):  
Takeshi Odagiri ◽  
Yoshiaki Kumagai ◽  
Motoyoshi Nakano ◽  
Takehiko Tanabe ◽  
Isao H. Suzuki ◽  
...  
Keyword(s):  
Excited States ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Doubly Excited States ◽  
Doubly Excited

Hydrogen escape from Mars is driven by seasonal and dust storm transport of water

Science ◽  
2020 ◽  
Vol 370 (6518) ◽  
pp. 824-831
Author(s):  
Shane W. Stone ◽  
Roger V. Yelle ◽  
Mehdi Benna ◽  
Daniel Y. Lo ◽  
Meredith K. Elrod ◽  
...  
Keyword(s):  
Dust Storm ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Dust Storms ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Mars Atmosphere ◽  
Water Abundance ◽  
Neutral Gas ◽  
Standard Models

Mars has lost most of its once-abundant water to space, leaving the planet cold and dry. In standard models, molecular hydrogen produced from water in the lower atmosphere diffuses into the upper atmosphere where it is dissociated, producing atomic hydrogen, which is lost. Using observations from the Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatile Evolution spacecraft, we demonstrate that water is instead transported directly to the upper atmosphere, then dissociated by ions to produce atomic hydrogen. The water abundance in the upper atmosphere varied seasonally, peaking in southern summer, and surged during dust storms, including the 2018 global dust storm. We calculate that this transport of water dominates the present-day loss of atomic hydrogen to space and influenced the evolution of Mars’ climate.

Photodissociation of H2 near Threshold Energies

1970 ◽  
Vol 25 (2) ◽  
pp. 237-242 ◽  
Author(s):  
F. J. Comes ◽  
U. Wenning
Keyword(s):  
Electric Field ◽  
Cross Section ◽  
Configuration Interaction ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Hydrogen Atoms ◽  
Dissociation Cross Section ◽  
Excited Molecules ◽  
Threshold Energies ◽  
Near Threshold

Abstract Measurements of the atomic hydrogen fluorescence (Lyα) yield important information on the dissociation behavior of molecular hydrogen under photon impact. Under certain assumptions the dissociation cross section of the molecule can be deduced from such experiments. By applying an appropriate electric field in the observation region those dissociations leading to the formation of metastable hydrogen atoms can be quantitatively determined. This information opens the possibility to describe the predissociation of the excited H2-molecules in the C-, D-and B″-states. The experiments show that the excited molecules in these particular states dissociate into H(1S) and H(2S) by configuration interaction with the B′-state.

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