Microwave Spectroscopy of High-$L$ ${\mathrm{H}}_2$ Rydberg States: The (0,1) 10 $G$, $H$, $I$, and $K$ States

Ten fine-structure intervals separating $n=10\mathrm{}$, $L=4, 5, 6, \mathrm{and} 7$ Rydberg states bound to the ($\nu =0, R=1\mathrm{}$) state of ${\mathrm{H}}_2^{+}$ have been measured to a precision of ±0.6 MHz with microwave-optical double-resonance techniques with a fast ${\mathrm{H}}_2$ beam. These measurements are sufficient to completely determine the relative positions of these states. Agreement with $a$ priori calculations of the level positions, with the extended polarization model, is found if the electric quadrupole moment of the (0,1) state of ${\mathrm{H}}_2^{+}$ is taken to be 1.6432(2) $e{a}_0^2$, which is 0.04(1)% larger than the best calculated values.