The Motion of Electrons in Carbon Monoxide

Abstract

Motion of electrons in carbon monoxide.—Formation of negative CO ions was found, in previous mobility experiments, to be extremely rare. This result has now been verified with CO generated by formic acid dripping into concentrated sulphuric acid and purified with great care. The very high mobilities obtained indicate clearly that an electron liberated in pure CO remains free. Electron mobility as a function of field and pressure was studied using alternating potentials with frequencies up to 340,000 cycles, generated by a vacuum tube oscillating circuit. At a pressure of 723 mm a mobility of 118 m/sec/volt/cm was measured, which decreased to 81.5 m as the field intensity increased from 4.5 to 48 volts/cm. The Townsend-Compton theory of mobility leads to the following equation for the speed of an electron in a field $x:v=\frac{a\left(\frac{x}{p}\right)}{\sqrt{B+\left(\frac{x}{p}\right)}}$. This leads to a relation between frequency and critical value of the field $X_1$ which is found to agree with the results for CO if $a=1.87\mathrm{} {\mathrm{}\left(10\right)\mathrm{}}^6$ and $B=.\mathrm{}005\mathrm{}$, the pressure being in mm Hg. This agreement suggests (1) that the mean free path is independent of the field, and (2) that the electron collisions with CO molecules are very inelastic.