Knowledge Bank

The laser induced fluorescence (LIF) excitation spectra of 3-pentoxy and tert-pentoxy radicals are obtained for the first time. The experiments were carried out in the wavelength range 345-400nm by laser photolysis or corresponding pentyl nitrites at 355nm. For 3-pentoxy, 15 vibronic bands were labled in three progressions with initial vibrational interval $578\pm 6cm-1$ corresponding C-O stretch mode. Two other unknown mode progressions have vibrational intervals of $596\pm 10$ and $590\pm 10cm-1$. The transition origin was tentatively assigned at $26437\pm 5cm-1$. For tert-pentoxy, the LIF spectrum consists 12 vibronic bands in three progressions. The C-O stretching vibration frequency and transition origin are derived to be $551\pm 10$ and $25491\pm 10cm-1$. The initial vibrational intervals of other two unknown modes are $587\pm 10$ and $631\pm 10cm-1$. New observations from LIF experiments on 10 additional large alkoxy radicals in the range from 335 to 400 nm are reported.