Experimental determination of repulsive potentials between alkali ions (Li+, K+, and Cs+) and hydrogen molecules (H2 and D2)

Integral elastic scattering cross sections of alkali ions (Li+, K+, and Cs+) in collision with room temperature hydrogen molecules (H2 and D2) were measured in the ion energy range 500–4000 eV. Some difference in the cross sections due to the replacement of the target gases were found in K+- and Cs+-hydrogen systems. Most of the difference can be explained by the difference of the target masses. The repulsive potentials deduced from the cross sections in a usual manner are represented by the following formulas independently of the isotopes: Li+: V(R) = 345 exp(−4.31 R), 0.88 < R < 1.43; K+: V(R) = 810 exp(−3.52 R), 1.33 < R < 1.98; and Cs+: V(R) = 1110 exp(− 3.26 R), 1.55 < R < 2.25; where V(R) is in units of electron volts and R in angstroms.