In addition to the significant impact on the progress of quantum mechanics at its early stage, the Stern-Gerlach experiment, the study on the interaction of atoms with a magnetic field, has led to the invention of nuclear magnetic resonance and magnetic resonance imaging. As this classic example, the investigation of particle-field interaction has been beneficial to the whole science area. The main topic of our group is experimental research and application of molecular interaction with various fields, such as nonresonant laser field and its combination with a static electric field. We exploit the state-dependent force imparted by the molecule-field interaction to spatially separate stereoisomers and their quantum states. Besides, in collaboration with the Fritz Haber Institute in Berlin, grazing incidence atom optics is investigated.