The modified Rouse model incorporating supplementary effects: I. Nonlinear modification for chain volume conservation and anisotropic friction

This study reexamines the constraint for volume conservation of the Rouse chain proposed recently (Kwon 2024). We provide conceivable reasoning for the constraint written in terms of the normal mode amplitude. Formulating the necessary number of constraints is verified to require vanishing correlation between distinct linear combinations of segmental vectors. Considering these observations, we prove that the normal mode amplitude is the only choice appropriate for the constraint. The constitutiv