A new diabatic representation of the coupled potential energy surfaces for Na(3<i>p</i> 2<i>P</i>)+H2→Na(3<i>s</i> 2<i>S</i>)+H2 or NaH+H

We present a new diabatic representation of the coupled potential energy surfaces for Na(3p 2P)+H2→Na(3s 2S)+H2 or NaH+H. The new representation is designed to yield, upon diagonalization, realistic values for the two lowest energy 2A′ adiabatic states at both asymptotes of the chemical reaction as well as near the conical intersection in the three-body interaction region. It is economical to evaluate and portable. It is suitable for dynamics calculations on both the quenching process and the electronically nonadiabatic chemical reaction.