The Experts below are selected from a list of 18 Experts worldwide ranked by ideXlab platform
K M Dunseath - One of the best experts on this subject based on the ideXlab platform.
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electron impact excitation of complex atoms and ions
Journal of Physics B, 1994Co-Authors: Philip G. Burke, V M Burke, K M DunseathAbstract:A new R-matrix approach for calculating cross sections and rate coefficients for electron-impact excitation of complex atoms and ions is described. This approach, based on an expansion of the Total Wavefunction in target configurations rather than in individual target states and taking advantage of the special status of the scattered electron in the collisional Wavefunction, enables the angular integrals to be performed very much more efficiently than hitherto. It also enables electron correlation effects in the target and in the electron-target collision complex to be treated consistently, eliminating pseudo-resonances which have caused serious difficulties in some earlier work. A major new program package RMATRX II has been written that implements this approach and, as an example, electron-impact excitation of Fe2+ is considered where the four target configurations 3d6, 3d54s, 3d54p and 3d54d are retained in the expansion of the Total Wavefunction. RMATRX II is compared with the standard R-matrix program package and is found to be much more efficient showing that accurate electron scattering calculations involving complex targets, such as the astrophysically important low ionization stages of iron-peak elements, are now possible.
Toshiki Sugimoto - One of the best experts on this subject based on the ideXlab platform.
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physisorption and ortho para conversion of molecular hydrogen on solid surfaces
Progress in Surface Science, 2013Co-Authors: Katsuyuki Fukutani, Toshiki SugimotoAbstract:Abstract Molecular hydrogen exists in nuclear-spin isomers of ortho and para species according to the Total nuclear spin. These species are correlated to the rotational states with even and odd rotational quantum numbers because of the symmetry of the Total Wavefunction with respect to the permutation of the two nuclei. Although interconversion between the ortho and para states is extremely slow in an isolated state, the conversion is promoted in a physisorption state via interaction with surfaces of not only magnetic but also diamagnetic materials. In a physisorption state, the rotational motion of hydrogen molecules is modified due to the potential anisotropy. The physisorption properties and interconversion rate of the ortho and para hydrogen have recently been investigated on well-defined surfaces, which allow detailed comparison with theory. Furthermore, relative abundance of the ortho and para hydrogen in astronomical circumstances has been reported in recent years, which often shows a value out of equilibrium with the environment temperature. Physisorption and ortho–para conversion on the surfaces of interstellar media are expected to enable deeper understanding of astronomical phenomena. In this article, we review recent progress of experimental and theoretical studies on the physisorption and ortho–para conversion of molecular hydrogen and its relevance to the recent astronomical observation.
Philip G. Burke - One of the best experts on this subject based on the ideXlab platform.
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electron impact excitation of complex atoms and ions
Journal of Physics B, 1994Co-Authors: Philip G. Burke, V M Burke, K M DunseathAbstract:A new R-matrix approach for calculating cross sections and rate coefficients for electron-impact excitation of complex atoms and ions is described. This approach, based on an expansion of the Total Wavefunction in target configurations rather than in individual target states and taking advantage of the special status of the scattered electron in the collisional Wavefunction, enables the angular integrals to be performed very much more efficiently than hitherto. It also enables electron correlation effects in the target and in the electron-target collision complex to be treated consistently, eliminating pseudo-resonances which have caused serious difficulties in some earlier work. A major new program package RMATRX II has been written that implements this approach and, as an example, electron-impact excitation of Fe2+ is considered where the four target configurations 3d6, 3d54s, 3d54p and 3d54d are retained in the expansion of the Total Wavefunction. RMATRX II is compared with the standard R-matrix program package and is found to be much more efficient showing that accurate electron scattering calculations involving complex targets, such as the astrophysically important low ionization stages of iron-peak elements, are now possible.
Katsuyuki Fukutani - One of the best experts on this subject based on the ideXlab platform.
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physisorption and ortho para conversion of molecular hydrogen on solid surfaces
Progress in Surface Science, 2013Co-Authors: Katsuyuki Fukutani, Toshiki SugimotoAbstract:Abstract Molecular hydrogen exists in nuclear-spin isomers of ortho and para species according to the Total nuclear spin. These species are correlated to the rotational states with even and odd rotational quantum numbers because of the symmetry of the Total Wavefunction with respect to the permutation of the two nuclei. Although interconversion between the ortho and para states is extremely slow in an isolated state, the conversion is promoted in a physisorption state via interaction with surfaces of not only magnetic but also diamagnetic materials. In a physisorption state, the rotational motion of hydrogen molecules is modified due to the potential anisotropy. The physisorption properties and interconversion rate of the ortho and para hydrogen have recently been investigated on well-defined surfaces, which allow detailed comparison with theory. Furthermore, relative abundance of the ortho and para hydrogen in astronomical circumstances has been reported in recent years, which often shows a value out of equilibrium with the environment temperature. Physisorption and ortho–para conversion on the surfaces of interstellar media are expected to enable deeper understanding of astronomical phenomena. In this article, we review recent progress of experimental and theoretical studies on the physisorption and ortho–para conversion of molecular hydrogen and its relevance to the recent astronomical observation.
V M Burke - One of the best experts on this subject based on the ideXlab platform.
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electron impact excitation of complex atoms and ions
Journal of Physics B, 1994Co-Authors: Philip G. Burke, V M Burke, K M DunseathAbstract:A new R-matrix approach for calculating cross sections and rate coefficients for electron-impact excitation of complex atoms and ions is described. This approach, based on an expansion of the Total Wavefunction in target configurations rather than in individual target states and taking advantage of the special status of the scattered electron in the collisional Wavefunction, enables the angular integrals to be performed very much more efficiently than hitherto. It also enables electron correlation effects in the target and in the electron-target collision complex to be treated consistently, eliminating pseudo-resonances which have caused serious difficulties in some earlier work. A major new program package RMATRX II has been written that implements this approach and, as an example, electron-impact excitation of Fe2+ is considered where the four target configurations 3d6, 3d54s, 3d54p and 3d54d are retained in the expansion of the Total Wavefunction. RMATRX II is compared with the standard R-matrix program package and is found to be much more efficient showing that accurate electron scattering calculations involving complex targets, such as the astrophysically important low ionization stages of iron-peak elements, are now possible.
