The conference will start in the afternoon of Sunday, Sep. 11th, and will end in the evening of Thursday, Sep. 15 with the conference dinner. The present edition of MOLEC, the XXI one, coincides with the 40th anniversary of the MOLEC Conference (founded in 1976). To celebrate this event, the first session of the conference on Sunday afternoon will be a special celebration session that will schedule two plenary lectures delivered by the two founders of the MOLEC Conference, Prof. J.P. Toennies and Prof. F.A. Gianturco. sponsored by Eur. Phys. J. D.