TY - GEN
T1 - Natural orbital analysis of ultrafast multielectron dynamics of molecules
AU - Kono, Hirohiko
AU - Oyamada, Takayuki
AU - Kato, Tsuyoshi
AU - Koseki, Shiro
PY - 2012
Y1 - 2012
N2 - The ionization dynamics of molecules in intense laser fields is investigated by using a time-dependent multiconfiguration theory for propagating the many-electron wave function in a grid space. We use the natural orbitals obtained from the many-electron wave function, i.e., the molecular orbitals obtained by diagonalizing the one-particle electron density matrix, to analyze the ionization process.We eliminate the ionizing portions of orbitals reaching the grid boundaries set far away from the nuclei; the occupation numbers of natural orbitals decrease due to ionization. The ionization probabilities of individual natural orbitals can be obtained from the accumulated reductions in occupation numbers. We also propose a new definition of molecular orbital energy in order to investigate the energetics of natural orbitals. It is shown that when energies are assigned to natural orbitals {φj(t)} as chemical potentials {εj(t)}, one can quantify a correction to the total electronic energy that represents electron correlation; that is, time-dependent correlation energy is introduced. Our attempt is illustrated by numerical results on the time-dependence of the spatial density and chemical potential for a H2 molecule interacting with an intense, near-infrared laser field. We compared the energy ζj(t) supplied by the applied field with the net energy gain Δεj(t) in the chemical potential for φj(t) and found that energy accepting orbitals of Δεj(t) > ζj(t) exhibit high ionization efficiency.
AB - The ionization dynamics of molecules in intense laser fields is investigated by using a time-dependent multiconfiguration theory for propagating the many-electron wave function in a grid space. We use the natural orbitals obtained from the many-electron wave function, i.e., the molecular orbitals obtained by diagonalizing the one-particle electron density matrix, to analyze the ionization process.We eliminate the ionizing portions of orbitals reaching the grid boundaries set far away from the nuclei; the occupation numbers of natural orbitals decrease due to ionization. The ionization probabilities of individual natural orbitals can be obtained from the accumulated reductions in occupation numbers. We also propose a new definition of molecular orbital energy in order to investigate the energetics of natural orbitals. It is shown that when energies are assigned to natural orbitals {φj(t)} as chemical potentials {εj(t)}, one can quantify a correction to the total electronic energy that represents electron correlation; that is, time-dependent correlation energy is introduced. Our attempt is illustrated by numerical results on the time-dependence of the spatial density and chemical potential for a H2 molecule interacting with an intense, near-infrared laser field. We compared the energy ζj(t) supplied by the applied field with the net energy gain Δεj(t) in the chemical potential for φj(t) and found that energy accepting orbitals of Δεj(t) > ζj(t) exhibit high ionization efficiency.
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U2 - 10.1007/978-3-642-28948-4_48
DO - 10.1007/978-3-642-28948-4_48
M3 - Conference contribution
AN - SCOPUS:84903829995
SN - 9783642289477
T3 - Springer Proceedings in Physics
SP - 289
EP - 297
BT - Multiphoton Processes and Attosecond Physics - Proceedings of the 12th Int. Conference on Multiphoton Processes, ICOMP 2011 and the 3rd International Conference on Attosecond Physics, ATTO 2011
PB - Springer Science and Business Media, LLC
T2 - 12th International Conference on Multiphoton Processes, ICOMP 2011 and the 3rd International Conference on Attosecond Physics, ATTO 2011
Y2 - 3 July 2011 through 8 July 2011
ER -