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Helix-coiled transition in heteropolymers. I. Ground-state energy

✍ Scribed by A. Vilenkin

Publisher
Wiley (John Wiley & Sons)
Year
1977
Tongue
English
Weight
722 KB
Volume
16
Category
Article
ISSN
0006-3525

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✦ Synopsis

A new technique is presented for treating the ground state of an heteropolymer with a random sequence of components. An exact system of equations is found for determining the ground state energy E which is equal to the polymer free energy f in the lowest-order approximation in TIV (Vl2 is the large "surface" energy arising a t the boundaries between coiled and "helical" sections: V >> T, Uk; U1 and -U2 are the free energies of the components counted from the corresponding coiled state energies). These equations are essentially simplified a t certain fixed values of the ratio U1/U2. For integer values of U2IU1 and U1IU2 a solution is obtained with an accuracy exp(-VIUk). The ground-state energy as a function of U1 and 112 is shown to be highly irregular: its derivatives have jumps a t an infinite number of points. These jumps provide a fine structure of the melting curves. A smoothed over the jumps function E' is found by way of analytic continuation from the integer values of UlIU2 and U2/Ul. The accuracy of the approximation f = E is estimated and the correctional term of order TIV is determined. *This work was done in partial fulfillment of the Ph.D. degree requirements of the Department of Physics, SUNY at Buffalo.

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