Efficient, Interpretable Atomistic Graph Neural Network Representation for Angle-dependent Properties and its Application to Optical Spectroscopy Prediction. - Tim Hsu; Nathan Keilbart; Stephen Weitzner; James Chapman 005; Penghao Xiao; Tuan Anh Pham; S. Roger Qiu; Xiao Chen; Brandon C. Wood (CoRR, 2021)