Year: 2021
Type: article
Abstract: Graphane is a layered material consisting of a sheet of hydrogenated graphene, with a C:H ratio of 1:1. We study isotopic effects in the properties of chair graphane, where H atoms alternate in a chairlike arrangement on both sides of the carbon layer. We use path-integral molecular dynamics simulations, which allows one to analyze the influence of nuclear quantum effects on equilibrium variables of materials. Finite-temperature properties of graphane are studied in the range 50–1500 K as functions of the isotopic mass of the constituent atoms, using an efficient tight-bonding potential. Results are presented for kinetic and internal energy, atomic mean-square displacements, fluctuations in the C–H bond direction, plus interatomic distances and layer area. At low temperature, substituting 13C for 12C gives a fractional change of −2.6 × 10−4 in C–C distance and −3.9 × 10−4 in the graphane layer area. Replacing 2H for 1H causes a larger fractional change in the C–H bond of −5.7 × 10−3. The isotopic effect in C–C bond distance increases (decreases) by applying a tensile (compressive) in-plane stress. These results are interpreted in terms of a quasiharmonic approximation for the vibrational modes. Similarities and differences with isotopic effects in graphene are discussed.
Authors: Carlos P. Herrero, Rafael Ramírez
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,254
Awards: G2239850215, G490073602, G6459294968
OpenAlex ID: W3171339611