This is the thirteenth supplement to the review "Photodissociation of Simple Molecules in the Gas Phase" which appeared in Vol.11 of the Research Reports (1986), hereafter called the Main Review. Supplements I-XII appeared in Vols.12 (1987) - 23 (1998), respectively. Continuing effort has been taken to collect new papers related to the title subject approximately up to July 1999. Some papers before July 1998 which have been inadvertently eluded from the Main Review and Supplements I-XII are added, together with some papers on IR predissociation of van der Waals molecules and clusters. The style closely follows those of the Main Review and Supplements I-XII. A book, "Photodissociation of Simple Molecules in the Gas Phase", a collected versio...