Quantum Lattice Contraction Induced by Transient Raman Process
The lattice contraction phenomenon found in time resolved X-ray diffraction and electron diffraction experiments is usually considered to be caused by photo-generated carriers. However, the quantum calculation under finite-time boundary conditions leads to a transient Raman process that directly connects optical transitions and lattice displacements. The lattice contraction phenomenon and the coherent phonon phenomenon can be explained well by the process.