In nuclei in the mass region around A = 190-200 a large number of regular dipole sequences have recently been found. In these bands the gain in angular momentum may not be created by collective rotation as is usual for more deformed nuclei, but stems from aligning the proton and neutron spins in the direction of the total spin axis. Calculations within the frame-work of the tilted axis cranking model reproduce the available experimental data and support the alignment picture.
Korten, W., Baldsiefen, G., Neffgen, M., Hübel, H., Chmel, S., Pohler, W., van Severen, U. J., Willsau, P., Frauendorf, S., Meng, J., Grawe, H., Heese, J., Kluge, H., Maier, K. H., Schubart, R., & Spohr, K. (1995). "Shears bands" in Pb nuclei – a new nuclear structure effect. Physica Scripta, T56, 44-46. https://doi.org/10.1088/0031-8949/1995/T56/007