Revisiting the generator coordinate approximation for calculating the ro‐vibrational energies of Hdocumentclass{article}pagestyle{empty}begin{document}$_{3}^{+}$end{document}

The Generator Coordinate Approximation, a relatively recent approximation formulated to solve systems of three or more bodies, is tested for its accuracy and viability by applying it to calculate the ro‐vibrational energies of the triatomic system H$_{3}^{+}$. We employ in this work a recently formulated basis called the Numerically Generated‐Discrete Variable Representation for the wave function and test it against the well‐known Finite Element Method basis. Comparison of the two results and with other results shows a tentative superiority of the Numerically Generated‐Discrete Variable Representation. In addition, many new physical properties of the Generator Coordinate Approximation were discovered. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 2028–2039, 2001