Calculated Potential-Energy Curves for CH+

Abstract

Ab initio calculations have been performed for states of C${\mathrm{H}}^{+}$ which arise from atomic ${\mathrm{C}}^{+}\left({}_{}{}^2{}_{}{}^{}P\right)$ and $\mathrm{H}\left({}_{}{}^2{}_{}{}^{}S\right)-X{}_{}{}^1{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$, $A{}_{}{}^1{}_{}{}^{}\Pi$, ${}_{}{}^3{}_{}{}^{}\Pi$, and ${}_{}{}^3{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$. Potential curves have been constructed over a wide range of internuclear distances. All computed energies are believed to be within 1 eV of their exact nonrelativistic Born-Oppenheimer value, and all energy differences are believed to have an accuracy of better than 0.3 eV. Results, with known experimental values in parentheses, are $R_e\left(X{}_{}{}^1{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}\right)=2.136\mathrm{}$ (2.137) a.u.; $D_e^0\left(X{}_{}{}^1{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}\right)=4.11\mathrm{}$ (4.21) eV; $R_e\left(A{}_{}{}^1{}_{}{}^{}\Pi \right)=2.232\mathrm{}$ (2.333) a.u.; $T_e\mathrm{}(X-A)=249\mathrm{}70$ (24146) ${\mathrm{cm}}^{-1\mathrm{}}$; $R_e\left({}_{}{}^3{}_{}{}^{}\Pi \right)=2.130\mathrm{}$ a.u. No evidence is found for a quasibound ${}_{}{}^3{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$ Rydberg state, although such behavior has been predicted for isoelectronic BH.