Understanding surface photochemistry from first principles: The case of CO-TiO2(1Â 1Â 0)

►Ab initio calculations within the embedding cluster approach were performed at CASPT2 level. ► We got first results on electronically excited states in CO-TiO2(1 1 0). ► We calculated 2D potential energy surfaces regarding desorption coordinate and polar angle. ► Our quantum dynamical calculations allow the detailed understanding of desorption process. ► This study serves as basis for upcoming experiments concerning laser-induced desorption.