On spectroscopy, control, and molecular information processing.

Implementing a logic machine on a single molecule was recently discussed with experimental roadmarks. Lasers were used to control the input and sometimes also the output of information with additional processing done via inter- and intramolecular dynamics. We examine the special requirements for an experiment that mimics a logic circuit. We use two-photon processes as physical examples of our considerations and discuss both combinational and sequential logic machines.