A Direct Measurement of the $7s\ ^2S_{1/2}\rightarrow$ $7p\ ^2P_{3/2}$ Transition Frequency in $^{226}$Ra$^{+}$.

We report a direct measurement of the $7s\ ^2S_{1/2}\rightarrow$ $7p\ ^2P_{3/2}$ electric-dipole transition frequency in $^{226}$Ra$^{+}$. With a single laser-cooled radium ion we determine the transition frequency to be 785722.11(3) GHz by directly driving the transition with frequency doubled light and measuring the frequency of the un-doubled light with an iodine reference. This measurement addresses a discrepancy of five combined standard deviations between previously reported values.