  More than 100 excited states of the Calcium-40 nucleus, with isospin 0, are
classified into rotational-vibrational bands of an intrinsic tetrahedral
structure. Almost all observed states below 8 MeV can be accommodated, as well
as many high-spin states above 8 MeV. The bands have some similarity to those
classifying states of Oxygen-16, but the A-mode vibrational frequency is lower
relative to the E-mode and F-mode frequencies than in Oxygen-16. Previously
identified rotational bands up to spin 16 and energy above 20 MeV are unified
here into a smaller number of tetrahedral bands.
