Hydrogen Bonding of H2+ to the He Atom: Energy Surface for Linear HeH2+

Abstract

Using pseudonatural orbitals as a basis for the superposition of configurations (SOC), we have calculated the adiabatic potential energy surfaces for linear HeHH⁺ and HHeH⁺. Except for the different basis set of Gaussian functions used, these calculations were carried out identically to one reported earlier for linear H₃. It is found that HeHH⁺ has a potential energy minimum ∼ 5 kcal deep for $R_{\mathrm{HeH}}\text{\hspace{0.17em}≅\hspace{0.17em}2.0}\mathrm{a.u.}$ , and $R_{\mathrm{HH}}\text{\hspace{0.17em}≅\hspace{0.17em}2.0}\mathrm{a.u.}$ This “hydrogen bonding” effect is given by the Hartree–Fock results and is little changed by SOC. HHeH⁺ is found to have a high potential energy barrier of ∼ 25 kcal for the symmetric complex, $R_{\mathrm{HHe}}{\mathrm{\hspace{0.17em}=\hspace{0.17em}R}}_{\mathrm{HeH}}\text{\hspace{0.17em}≅\hspace{0.17em}2.1}\mathrm{a.u.}$