2016 年 58 巻 1 号 p. 48-53
The first sharp diffraction peak (FSDP) reflects the intermediate-range order in disordered systems. Here we start from the FSDP in elemental liquid, liquid phosphorus, and we glance similarities between the pressure dependence of the FSDP in SiO2 glass and that in a polymer [isotactic poly(4-methyl-1-pentene)] in its melted state. These FSDP are related to voids. In contrast, some first peaks in polymers are related to nanophase separation.