Pairing reduction due to the blocking effect

Pairing reduction in deformed nuclei due to the blocking effect is treated exactly with the particle-number-conserving method. Merely due to the blocking effect the gap parameter Δ becomes configuration dependent. The pairing reduction δ(ν_o) depends sensitively on the single-particle level distribution near the Fermi surface and on the location of the blocked level ν_o relative to the Fermi surface. The pairing reduction per blocked level near the Fermi surface is about $\text{δ(ν}{}_{\mathrm{o}}\text{) ≈}\text{1}\text{2}\text{d}$, where d is the average spacing of the Nilsson levels, and decreases rapidly with |ε_νo-λ|. With an increasing number of blocked levels near the Fermi surface the pairing reduction increases dramatically. In some special cases pairing reduction may be negative. Three anomalous even-odd shifts in band-crossing frequencies in ¹⁶¹Er, ¹⁷³W and ¹⁸¹Os are analyzed.