Experimental Determination of the Repulsive Potentials between K+ Ions and Rare-Gas Atoms

Abstract

Integral elastic scattering cross sections have been measured by the attenuation method for potassium ions with an energy selected in the range of 500–4000 eV scattered by room‐temperature He, Ne, Ar, and Kr atoms through effective laboratory angles greater than 5×10⁻³ rad. The repulsive potentials have been derived from the measured values of the cross sections with allowance for the density distribution across the beam in the collision chamber. The potentials are well represented by the following expressions: $$\begin{array}{c}\mathrm{He}\text{:\hspace{0.17em}\hspace{0.17em}\hspace{0.17em} V(r) = 1110\hspace{0.17em}}\exp \text{(−4.15r)\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}}\mathrm{for}\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em} 1.23 < r < 1.77,}\\ \mathrm{Ne}\text{:\hspace{0.17em}\hspace{0.17em}\hspace{0.17em} V(r) = 4910\hspace{0.17em}}\exp \text{(−4.40r)\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}}\mathrm{for}\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em} 1.55 < r < 2.04,}\\ \mathrm{Ar}\text{:\hspace{0.17em}\hspace{0.17em}\hspace{0.17em} V(r) = 2920\hspace{0.17em}}\exp \text{(−3.46r)\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}}\mathrm{for}\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em} 1.79 < r < 2.43,}\end{array}$$ and $$\begin{array}{c}\mathrm{Kr}\text{:\hspace{0.17em}\hspace{0.17em}\hspace{0.17em} V(r) = 6420\hspace{0.17em}}\exp \text{(−3.69r)\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}}\mathrm{for}\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em} 1.92 < r < 1.53,}\end{array}$$ where V(r) is in electron volts and r in angstroms.