This book describes the manipulation of molecular properties, such as orientation, structure, and dynamics, of small molecules and molecular clusters isolated in cold inert matrices by using unprecedentedly strong external electrostatic fields. Manipulation of molecules with controllable external forces is a dream of chemists. Molecules are inherently quantum-mechanical systems, control of which potentially can lead to quantum technology, such as quantum sensing and computing. This book demonstrates a combination of the ice film nanocapacitor method and the matrix isolation technique enabled the application of intense external dc electric fields across the isolated molecules and molecular clusters. Changes in molecular states induced by fields were monitored by means of vibrational spectroscopy. Also, the book presents manipulations of the inversion tunneling dynamics of ammonia molecule and the dislocation of acidic proton in hydrogen chloride-water complex. The book shows that the vibrational spectroscopy with the aid of unprecedentedly strong dc electric field can provide rich information on the electrostatic behaviors of molecules and molecular clusters, which underlie the understanding of intermolecular processes and molecular manipulation.