impurity center造句

• Those holes and electrons are captured successively by impurity centers exciting certain metastable states not accessible to the excitons.
• The value f _ i > 1 per a single impurity center should not be surprising because the transition is a collective process including many electrons in the region of the volume of about a _ i ^ 3 > > v.
• Anomalously high intensity of the impurity-exciton lines indicate their giant oscillator strength of about f _ i \ sim10 per impurity center while the oscillator strength of free excitons is only of about f _ { \ rm ex } \ sim10 ^ {-4 } per unit cell.