アイテム詳細

要旨

When investigating photochemical dynamics, one usually measures the time for disappearance of the primary excited state or the appearance of the product state or the total time the molecule needs for traveling from the former to the latter. Quantum chemistry predicts, however, that molecules often pas on this way via intermediate potential energy surfaces and conical intersections, the path sometimes branching and changing direction. In the conventional methods this intermediate region remains in the dark. We show that probing by intense-laser field ionization and mass-selective detection provides surprisingly many time constants which can reveal this region and thus practically allow to 'look into the black box', it is thus possible to monitor the molecule's pathway all along the potential energy surfaces from the initially excited region down to the ground state of the product. Even driving forces can be recognized. We discuss these and other advantages, but also pitfalls of this method and compare it with other methods of probing.