Low Frequency Mechanical Modes of Viral Capsids: An Atomistic Approach

We present a method for the calculation of the low frequency vibrational modes and frequencies of viral capsids, or other large molecules, where the modes are modeled with atomic detail. Extending ideas from electronic structure theory, an energy functional is used to find modes of a classical dynamical matrix below a fixed (pseudo-Fermi) level. The icosahedral satellite tobacco necrosis virus is modeled as an example. We find that atoms around the $C5$ and $C3$ axis have small relative displacement while the $\beta$ sheet body shows gliding motion.