| dc.description.abstract | tweezers, or shear flow made it feasible for detailed experimental studies of the
conformations of single long molecules, especially in helical double-stranded DNA
molecules, so we hope to realize it more theoretically and by simulations. In the thesis,
the static properties of a single stiff helical polymer chain under stretching is
investigated by Monte Carlo simulations with the bond-fluctuation model. The
primary purpose is to describe the change of conformations and the persistence length
of a helical chain due to the rigidity of the chain and measure the extension of the
chain under an external stretching force. We attempt to employ the measures such as
the correlation function of bond vectors, average of the Writhe, radius gyrations,
dihedral angles and bending angles to describe the helical structures. At the high
scaled temperatures, the chain behaves like a disordered coil chain, however, at low
scaled temperatures, the local he lical structures emerge. This properties can be
verified by the above the measured quantities. As for stretching the helical polymer
chain, we focus deformation of the chain on the linear force regime and non-linear
Pincus regime mainly because both of the regimes have the universal scaling
behaviors. We observed that the width of the regime from the linear to Pincus
behaviors for the chain with the rigidity parameter becomes more narrow than one of
the flexible chain involving only excluded volume interactions. Finally, our
simulation data also show the changes of geometry such as sinθ, sinψ, writhe, and
the pitch due to the stretching force. | en_US |