Isotopic effects in chair graphane

Graphane is a layered material consisting of sheet hydrogenated graphene, with C:H ratio 1:1. We study isotopic effects in the properties chair graphane, where H atoms alternate chairlike arrangement on both sides carbon layer. use path-integral molecular dynamics simulations, which allows one to analyze influence nuclear quantum equilibrium variables materials. Finite-temperature graphane are studied range 50--1500~K as functions mass constituent atoms, using an efficient tight-bonding potential. Results presented for kinetic and internal energy, atomic mean-square displacements, fluctuations C--H bond direction, plus interatomic distances layer area. At low temperature, substituting $^{13}$C $^{12}$C gives fractional change $-2.6 \times 10^{-4}$ C--C distance $-3.9 Replacing $^2$H $^1$H causes larger $-5.7 10^{-3}$. The effect increases (decreases) by applying tensile (compressive) in-plane stress. These results interpreted terms quasiharmonic approximation vibrational modes. Similarities differences graphene discussed.