Effects of phase on differential ionization cross sections

The data base for understanding interactions of radiation with matter is obtained primarily from experiments in the gas phase; however, in radiological physics the authors are mostly concerned with energy deposition in a condensed medium. Hence, it is important to understand how intermolecular forces in condensed matter effect energy transfer and degradation. Phase effects can be divided into two categories. 1) effects of phase on the transfer of energy from radiation to matter and 2) the phase dependence of energy degradation and formation of chemical species. The former, which is much better understood at present, is discussed in this section