The LiF:F2+** laser as been shown to provide high power (hundreds of mJ), efficient (tens of %), room temperature stable laser operation tunable from 800 nm to nearly 1210 nm. However, no reasonable explanations were provided for such an ultrabroadband tuning capability using this active medium. This work describes the mechanism of the ultrabroadband lasing from LiF:F2+** under Alexandrite laser pumping. Alexandrite laser pump radiation corresponds to the region of spectral overlapping in the absorption bands of two color center in LiF, namely F2+** and a new F2+**-like center, conclusively discovered in this work. Using the Alexandrite laser's excitation, we can achieve simultaneous population inversion in both centers making F2+** and the F2F+**-like centers, the primary color centers responsible for the ultrabroadband tunability. This work details the temperature-dependent spectroscopic measurements of these two color centers and the resulting laser characteristics. Absorption and fluorescence measurements were performed from 300 K to 13 K. The room temperature (RT) absorption data shows that the F2+** center has maximum absorption at (lambda) 0abs equals 614.5 nm and FWHM, (Delta) v equals 3819 cm-1; the F2+**- like center has RT absorption at (lambda) oabs equals 813.4 nm and FWHM, (Delta) v equals 3592 cm-1. The fluorescence of both centers was measured using several excitation wavelengths from 532 nm to 778 nm. F2+** demonstrated fluorescence emission from 765 - 1080 nm, corresponding to 10% of maximum, and F2+**-like from roughly 890 - 1400 nm, with fluorescence maxima at (lambda) fl equals 905 nm and (lambda) fl equals 1098 nm, respectively.