PARTICLE-HOLE MULTIPLETS IN $sup 88$Y AND THE MECHANISM OF THE ($sup 3$He,t) REACTION.

The reactions ${\mathrm{Sr}}^{87}({\mathrm{He}}^{3},d){\mathrm{Y}}^{88}$, ${\mathrm{Sr}}^{87}(\ensuremath{\alpha},t){\mathrm{Y}}^{88}$, ${\mathrm{Sr}}^{88}({\mathrm{He}}^{3},t){\mathrm{Y}}^{88}$, and ${\mathrm{Y}}^{89}({\mathrm{He}}^{3},\ensuremath{\alpha}){\mathrm{Y}}^{88}$ were studied and the data were used to construct a level scheme of ${\mathrm{Y}}^{88}$. Spin and parity assignments are suggested for many new states below 2.5 MeV. The principal components of their wave functions are interpreted in terms of particle-hole multiplets. The angular distributions from the (${\mathrm{He}}^{3},t$) reaction are not well fitted by distorted-wave calculations. Some systematic patterns of the (${\mathrm{He}}^{3},t$) reaction mechanism are noted, but the exceptions indicate that the conventional treatment of the (${\mathrm{He}}^{3},t$) reaction may be far from adequate.