IP determination and 1+1 REMPI spectrum of SiO at 210-220 nm with implications for SiO${}^{+}$ ion trap loading

The 1+1 REMPI spectrum of SiO in the 210-220 nm range is recorded. Observed bands are assigned to the $A-X$ vibrational bands $(v\mathrm{‘}\mathrm{‘}=0-3,v\mathrm{‘}=5-10)$ and a tentative assignment is given to the 2-photon transition from $X$ to the n=12-13 $[X^2{\mathrm{\Sigma }}^{+},v^{+}=1]$ Rydberg states at 216-217 nm. We estimate the IP of SiO to be 11.59(1) eV. The SiO${}^{+}$ cation has previously been identified as a molecular candidate amenable to laser control. Our work allows us to identify an efficient method for loading cold SiO${}^{+}$ from an ablated sample of SiO into an ion trap via the $(5,0)$ $A-X$ band at 213.977 nm.