TY  - JOUR
A1  - Schäfer-Bung, Boris
T1  - The interplay of wave packet dephasing, optimization efficiency, and target state population in optimally controlled isotope selective photoionization
N2  - The mutual dependencies of characteristic quantities for an isotope selective photoionization, namely optimization efficiency, target state population, and wave packet dephasing are presented for the NaK dimer. A pre- optimized pulse shape obtained from the maximization of the isotopomer ratio 23Na39K/23Na41K for the first excited electronic state serves as an initial guess for the subsequent optimization. For the ionization it provides almost vanishing population of the heavier ionic isotopomer and an ionic isotopomer ratio which is significant higher than the findings obtained from former investigations. The wave packet motions on the first excited state of the neutral molecule are in phase for both isotopomers. The optimization procedure, i.e. the simultaneous maximization of the 23Na39K+ photoionization yield and the minimization of the 23Na41K+ photoionization yield for the electronic ground state is based on optimal control theory and leads to a rise of ionic ground state population for both isotopomers related to a significant wave packet dephasing. Upon optimization the isotopomer ratio of the yields falls due to incidental resonances of vibronic transitions. The interplay of the observables are discussed and compared with the values obtained from an optimization which was started from a pure Gaussian pulse shape.
Y1  - 2008
UR  - http://dx.doi.org/10.1016/j.chemphys.2007.11.002
SN  - 0301-0104
ER  - 
TY  - JOUR
A1  - Schäfer-Bung, Boris
A1  - Nest, Mathias
T1  - Correlated dynamics of electrons with reduced 2-electron density matrices
N2  - We present an approach to the correlated dynamics of many-electron systems. We show, that the two-electron reduced density matrix (2RDM) can provide a suitable description of the real time evolution of a system. To achieve this, the hierarchy of equations of motion must be truncated in a practical way. Also, the computational effort, given that the 2RDM is represented by products of two-electron determinants, is discussed, and numerical model calculations are presented.
Y1  - 2008
UR  - http://dx.doi.org/10.1103/PhysRevA.78.012512
ER  -