There currently are two optical isomer specifications within JTHERGAS. The first is that around a carbon atom. This means that the general carbon atom is used. Each carbon atom in which every ligand is different (corresponding to four groups of one element in each group) contributes one optical isomer. A second optical isomer is defined as a hydroperoxy group (OOH) which induces an optical isomer due to the high rotation energy barrier. The symmetry structure is ROOH, where R is left unspecified. A given molecule can have several optical isomer contributions.