Formation of chemically bound positively charged radiation defect induced by negative muon in diamond crystals

• Formation of a chemically bound to diamond lattice μB+ radiation defect is considered.
• Quantum-chemical calculations of the μB+ defect in a diamond lattice were performed.
• Rate formation of a positively charged μB+ center in diamond is estimated.

The formation process of a positively charged radiation defect bound chemically with a diamond lattice is considered. This defect originates as a result of a negative muon capture by a carbon nucleus and formation of the so called “pseudo-boron” muonic atom μB. Numerical calculations (Antipov et al., 2012) of the neutralization kinetics of the radiation defect have shown that it lacks a time interval for neutralization during electron trapping in a track within a muon life-time τμ = 2.2∙10− 6 s. Therefore, there appeared a necessity for considering alternative neutralization processes. Thus, a model of the positively charged μB+ defect formation chemically bonded with a lattice, is suggested. Quantum-chemical calculations of a defect chemical bond energy with lattice atoms were carried out. Based on numerical calculations, estimates of formation rate w of the chemically bound positively charged defect were obtained, yielding w ≈ 1.7∙1011 s− 1. It is shown that defect neutralization is caused by the electron filling of a broken chemical bond, and this is characterized by the lattice relaxation time.