AbstractThe Ga2 spectrum with its no‐phonon transitions at 1.0472 eV (triplet) and 1.0501 eV (singlet) is studied as a function of temperature and in magnetic and uniaxial stress fields. Like in the case of Ga3, this singlet—triplet pair exciton emission is accompanied by thermalizing higher energy singlet lines s (+2.9 meV), s*(+3.8 meV), and s**(+4.7 meV). Localized vibrational mode replicas of the triplet/singlet are observed with ħω = 11.0 meV and ħω = 18.8 meV, along with lattice modes and combination lines. Zeeman measurements indicate that the center belongs to the rhombic I (C2v) point group symmetry, and the triplet transition splits asgx= 2.7,gy= 2.1, andgz= 1.6. The effectiveg‐value of the exciton,geff= 2.13, is consistent with thermal data suggesting the hole to be the tightly bound particle (≈100 meV) whereas the electron is bound by only ≈23 meV. Uniaxial stress measurements can be explained in terms of valley—orbit interactions by the weakly bound “pseudo‐donor” electron. Finally, the gallium related centers Ga 1, Ga2,