We use the ground state depletion dynamics to assign the fast and slow transport axes. For the single pulse data (Fig. , dark blue), the ground state depletion magnitude at the fully overlapped region is the largest, indicating that we measure the greatest population of excited state species when photoexciting at (0, 0). Between 5-100 ps, photoexcitation at (0, 2.7) leads to 86% of the ground state depletion as compared to the fully overlapped region, while photoexcitation at (2.7, 0) results in 60% of the fully overlapped depletion magnitude. This indicates that more excited state species travel along the a axis than the b axis into the probing region. This is to be expected as previous work has established the a axis as the fast exciton transport axis and the b axis as the slow transport axis. Despite some spatial overlap between the actinic and Raman probe beams, we are able to measure exciton transport as the beams are not fully overlapped. The area of overlap at 0 ps is approximately 25% of the total area of the probe beam, and thus we expect that some of depletion signal results from this region. However, if the depletion resulted exclusively from the overlapped regions, then the magnitude would be equivalent at each spatially offset position. Since we see 26% more depletion along the fast axis with the single pulse excitation between 5 and 100 ps, however, we are confident that we observe exciton transport. Given reported exciton diffusion constants in polyacene crystals, we would expect exciton transport into the probing region to result in approximately a 2% increase in signal over the duration of the experiment. We instead observe depletion magnitudes that are much larger than these estimates at offset photoexcitation locations. We attribute this large magnitude to a change in resonance conditions of the triplet state. When the excited state is more electronically resonant with the Raman pump as compared to the ground state, FSR spectra are known to show large ground state depletion values. This apparent increase in the depletion magnitude does not, therefore, directly reflect the true population of the excited state since we cannot untangle the relative populations of triplet and singlet excitons. However, comparing changes in relative ground state depletion magnitude along the fast and slow axes with amplification of each phonon mode still gives crucial insights into the role of intermolecular vibrations in mediating exciton transport in pentacene.