Bm. Dinelli et al., SPECTROSCOPICALLY DETERMINED BORN-OPPENHEIMER AND ADIABATIC SURFACES FOR H-3(-3(+)(), H2D+, D2H+, AND D), The Journal of chemical physics, 103(24), 1995, pp. 10433-10438
High resolution spectroscopic data for H-3(+), H2D+, D2H+, and D-3(+)
is used to determine effective, mass-dependent potential energy surfac
es for each isotopomers. These surfaces are expressed as a sum of the
mass-independent Born-Oppenheimer (BO) potential and a mass dependent
adiabatic correction. For H-3(+) and D-3(+) the adiabatic correction i
s a single surface of the same symmetry and functional form as the BO
surface. For H2D+ and D2H+ a second, lower symmetry surface is require
d. Fits to all three surfaces were started from recent, high quality a
b initio calculations. The standard deviations for fits using all the
available data with J less than or equal to 9 are 0.015 cm(-1) for H-3
(+), 0.010 (-1) for H2D+ and D2H+ combined, and 0.015 cm(-1) for D-3(). These values are close to the intrinsic experimental error of much
of the data and improve on the corresponding ab initio surfaces by at
least an order of magnitude. The fits are very compact: nearly 1600 da
ta are fitted by adjusting 36 constants and freezing 51 at their ab in
itio values. (C) 1995 American Institute of Physics.