The effect of a neon matrix on the hyperfine structure of CH+4. A model study

The influence of up to six Ne atoms on the isotropic hyperfine (hf) coupling constants of the hydrogen atoms in CH+4 is investigated using density functional theory. It is found that at very short NeH distances (R = 1.8 A), the hf structure is strongly affected, whereas at the more realistic van der Waals distance (R ≈ 2.5 A), the methane radical experiences a very weak field from the surrounding Ne atoms. At larger distances, the effects of the Ne matrix are negligible. It is furthermore found that at small R, the changes in aiso (H) are strongly dependent on the relative positions of the Ne atoms.