Collisional quenching of electronically excited germanium atoms, Ge[4p2(1S0)], by atomic absorption spectroscopy

Abstract

Electronically excited germanium atoms, Ge[4p²(¹S₀)], 2.029 eV above the 4p²(³P₀) ground state, have been generated by pulsed irradiation of Ge(CH₃)₄ and monitored photoelectrically in absorption by time-resolved attenuation of atomic resonance radiation at λ= 274.04 nm [4d(¹P⁰₁)â†� 4p²(¹S₀)]. Absolute second order rate constants (k_Q±∼ 30 %, cm³ molecule^–1 s^–1, 300 K) are reported for the collisional quenching of this atomic state by various gases, namely, Xe(1.8 × 10^–13) D₂(1.4 × 10^–12) H₂(1.5 × 10^–11) O₂(4.2 × 10^–11) N₂(1.8 × 10^–12) NO(2.0 × 10^–11) CO(1.8 × 10^–12) N₂O(3.1 × 10^–12) CO₂(3.9 × 10^–13) CF₄(1.6 × 10^–12) CH₄(1.3 × 10^–11) SF₆(8.5 × 10^–14) CF₃H(1.3 × 10^–11) C₂H₂(1.1 × 10^–10) C₂H₄(2.3 × 10^–10) Ge(CH₃)₄(8.0 × 10^–10). The results are compared with analogous data for other group IV atoms, namely, those for C(2¹S₀), Sn(5¹S₀) and Pb(6¹S₀), and discussed, where appropriate, within the context of symmetry arguments on the nature of the potential surfaces involved on both the basis of the weak spin orbit coupling approximation and (J,Ω) coupling. The feasibility of constructing a pulsed laser based on the transition Ge(4¹S₀)→ Ge(4¹D₂)(λ= 1.0820 µm) is considered in view of the population inversion observed between these two states in these experiments.