Spectroscopy at very high pressures. XIII. Refracting beam condenser for infrared spectroscopy with a diamond anvil cell

The optical problems associated with infrared spectroscopy at very high pressures in a diamond anvil cell are considered and the main limitations identified. The principal difficulty is the conflict between optical requirements, which indicate the need for relatively large unsupported areas of diamond, and mechanical requirements which work conversely. A simple refracting beam condenser is described and the problems of coupling it to spectrophotometers are indicated.