We present the analysis of K 2 short cadence data of the rapidly oscillating Ap ( roAp ) star , 33 Librae ( HD 137949 ) .
The precision afforded to the K 2 data allow us to identify at least 11 pulsation modes in this star , compared to the three previously reported .
Reoccurring separations between these modes leads us to suggest a large frequency separation , \Delta \nu , of 78.9 \muup Hz , twice that reported in the literature .
Other frequency separations we detect may represent the small frequency separation , \delta \nu , but this is inconclusive at this stage due to magnetic perturbation of the frequencies .
Due to the highly non-linear pulsation in 33 Lib , we identify harmonics to four times the principal frequency .
Furthermore , we note a unique occurrence of non-linear interactions of the 11 identified modes .
The frequency separations of the modes around the principal frequency are replicated around the first harmonic , with some interaction with the second harmonic also .
Such a phenomenon has not been seen in roAp stars before .
With revised stellar parameters , linear non-adiabatic modelling of 33 Lib shows that the pulsations are not greater than the acoustic cutoff frequency , and that the \kappa -mechanism can excite the observed modes .
Our observations are consistent with 33 Lib having a rotation period much larger than 88 d as presented in the literature .