Excitons in molecular crystals : theory and applications / D. F. Craig, S. H. Walmsley. Craig, David Parker, 1919- Walmsley, S. H., joint author. Exciton theory. Crystals. QD941 .C7 539.776 CRE Includes bibliographical references and index. New York : Benjamin, 1968. 1968. 1968 Text xi, 172 p. : eng Frontiers in chemistry