CELL BIOPHYSICS 5, 163-187 (1983) Differential Scattering of Circularly Polarized Light as a Unique Probe of Polynucleosome Superstructures A Simulation by Multiple Scattering of Dipoles S. ZIETZ, *'t'* A. BELMONT,* AND C. NICOLINI* "PDepartment of Mathematical Sciences, Drexel University, Philadelphia, PA 19104 and SDivision of Biophysics, Temple University Health Sciences Center, Philadelphia, PA 19104 Received February 28, 1983; Accepted June 14, 1983 Abstract A theoretical approach to modeling Circular Intensity Differential Scattering (CIDS) of native chromatin as multiple scattering of dipoles is discussed without the Born ap- proximation. The model can explain the experimental data in the literature. It is shown that CIDS contains more structural information than does total light scattering and to a good approximation is independent of the length of the scattering molecules. Finally, CIDS in conjunction with traditional light scattering measurements should aid in dis- criminating between various alternative models of higher order chromatin structure now being proposed. Generalization of this theoretical study to other complex biomolecular structures, is also briefly discussed. Index Entries: Circular Intensity Differential Scattering, of chromatin; differen- tial scattering, of chromatin; polarized light scattering studies, on chromatin; polynucleosome superstructures, differential scattering of; dipoles, multiple scatter- ing of. ~Copyright 1983 by Humana Press inc. All fights of any nature whatsoever reserved. 0163~992/83/090ff4) 163$5.00 163