  We present a model for semiflexible polymers in Hamiltonian formulation which
interpolates between a Rouse chain and worm-like chain. Both models are
realized as limits for the parameters. The model parameters can also be chosen
to match the experimental force-extension curve for double-stranded DNA. Near
the ground state of the Hamiltonian, the eigenvalues for the longitudinal
(stretching) and the transversal (bending) modes of a chain with N springs,
indexed by p, scale as lambda_lp ~ (p/N)^2 and lambda_tp ~ p^2(p-1)^2/N^4
respectively for small p. We also show that the associated decay times tau_p ~
(N/p)^4 will not be observed if they exceed the orientational time scale tau_r
~ N^3 for an equally-long rigid rod, as the driven decay is then washed out by
diffusive motion.
