Excitation of the He iiλ4686Å Line by Electron Impact

Absolute cross sections for the excitation of the Heii $\lambda 4686$ Å line by electron impact on helium have been measured as a function of electron energy from threshold to 400 eV. A rough comparison of the results is made with expected cross sections from the calculations of Dalgarno and McDowell. Excitation of the He i $\lambda 4713$ Å line ($4{}_{}{}^3{}_{}{}^{}S\to 2{}_{}{}^3{}_{}{}^{}P$ transition) was also measured and the results compared with those of other investigators.