Knowledge Bank

“A detailed investigation is made of the Rees modification of the Rydberg-Klein graphical method of calculating potential energy curves without the use of empirical functions (such as Morse functions). The X $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma e$ ground state of $H2$ is chosen for investigation because of the large amount of both experimental and theoretical information available. It is found that a slight extension of the Rees procedure yields an accurate potential curve very rapidly, and hence the use of empirical functions is questionable when data are available and accurate curves are desired. Our calculations for $H2$ join smoothly with the accurate quantum mechanical calculations of Dalgamo and Lynn, valid at large internuclear separations. The resulting “most likely” potential energy curve agrees between 0.5A and 2.0A with a similar curve given previously by Hirschfelder and Linnett, but at smaller and larger distances differs appreciably from the Hirsehfelder-Linnett curve.”