Measurement of the bending rigidity and spontaneous curvature of fluid membranes in simulations

TL;DR

This study evaluates numerical methods for measuring bending rigidity and spontaneous curvature of fluid membranes in simulations, highlighting the importance of cutoff frequency in thermal undulation analysis and comparing different estimation techniques.

Contribution

It introduces and compares multiple numerical methods for accurately estimating membrane properties, emphasizing the inverse power-spectrum fit approach.

Findings

Inverse power-spectrum fit minimizes estimation error.

Methods for spontaneous curvature estimation agree well.

Cutoff frequency significantly affects bending rigidity estimates.

Abstract

Several numerical methods for measuring the bending rigidity and the spontaneous curvature of fluid membranes are studied using two types of meshless membrane models. The bending rigidity is estimated from the thermal undulations of planar and tubular membranes and the axial force of tubular membranes. We found a large dependence of its estimate value from the thermal undulation analysis on the upper-cutoff frequency q_{cut} of the least squares fit. The inverse power-spectrum fit with an extrapolation to q_{cut} -> 0 yields the smallest estimation error among the investigated methods. The spontaneous curvature is estimated from the axial force of tubular membranes and the average curvature of bent membrane stripes. The results of these methods show good agreement with each other.