A great number of matters behave dramatically different from what we know at ambient
conditions when they are subjected to extreme pressure and temperature conditions. For
example, water can transform to ice at low pressure and room temperature. Similarly, carbon
dioxide (dry ice) becomes molecular solid at <1 GPa and 300 K. When pressure greater than 10
GPa, it transforms to orthorhombic structure. Further compression to above 37-50 GPa, carbon
dioxide lose its long-range order and become non-molecular solids. Under high pressure oxides
may change their colors and close their band gaps. Furthermore, charge transfer may also occur
in responding to the new extreme environment, such as TlReO4 and TmTe.
In this talk, I will introduce the high pressure diamond-anvil cell apparatus and its applications to
structure determinations and thermodynamic and physical properties (stress, elasticity)
measurements using Raman, IR and synchrotron X-ray.