On the Origin of 21/2⁺ Yrast Trap in ⁹³Mo

Isomerism of the high-spin yrast 21/2⁺ states of the N=51 isotones ⁹¹Zr, ⁹³Mo and ⁹⁵Ru has been investigated using the shell model calculations. It is found that the low-j πp_1/2 is responsible for the only yrast trap in ⁹³Mo. In addition, the relatively smaller 10₁⁺-12₁⁺ level spacing in ⁹⁴Mo has been found by investigating the systematics of the 10₁⁺-12₁⁺ level structures in the N=52 isotones ⁹²Zr, ⁹⁴Mo and ⁹⁶Ru. This result provides a supplementary argument to the origin of the 21/2⁺ yrast trap in ⁹³Mo from the viewpoint of the similarity between the configurations of 10₁⁺-12₁⁺ states in ⁹⁴Mo and those of 17/2₁⁺-21/2₁⁺ states in ⁹³Mo.