 After the NSDAP came to power in Germany in 1933 , Franck resigned his post in protest against the dismissal of fellow academics . He assisted Frederick Lindemann in helping dismissed Jewish scientists find work overseas , before he left Germany in November 1933 . After a year at the Niels Bohr Institute in Denmark , he moved to the United States , where he worked at Johns Hopkins University in Baltimore and then the University of Chicago . During this period he became interested in photosynthesis . 
