However, none of the B peaks appear in the FC simulations. This observation, along with the different PADs seen for the B peaks, suggests that they involve FC-forbidden transitions of non-totally symmetric vibrational modes that become allowed only through Herzberg-Teller coupling with a lowlying excited state of neutral TiO(OH)2. As seen in NO3, effects of this type also lead to differences in the low-energy photodetachment cross sections for peaks that are vibronically vs. FC-allowed, and indeed the B peaks are seen only in the high-resolution scans where the eKE is low. The spacing between peaks A1 and B1 is 60 cm -1 , which is close to the calculated frequency for the 8 umbrella mode of TiO(OH)2, a non-totally symmetric mode with b1 symmetry, and in fact all the B peaks can be assigned to excitations of this mode. Hence, we attribute the B peaks to the presence of Herzberg-Teller coupling between the 1 A1 ground state and an as yet unidentified 1 B1 excited state of TiO(OH)2.