Geometric quantities of lower doubly excited bound states of helium

Expectation values of single electron and interelectronic geometric quantities such as \langle r\rangle, \langle r_12\rangle, \langle r_<\rangle, \langle r_>\rangle, \langle \cos\theta_12\rangle and \langle \theta_12\rangle are calculated for doubly excited 2\rm pn\rm p\,^1P^\,\rm e\,(3\leq n\leq5),\, 2\rm pn\rm p\,^3\!P^\,\rm e\,(2\leq n\leq5) and 2\rm pn\rm d\,^1,3D^\,\rm o\,(3\leq n\leq5) states of helium using Hylleraas-B-spline basis set. The energy levels converge to at least 10 significant digits in our calculations. The extrapolated values of geometric quantities except for \langle \theta_12\rangle reach 10 significant digits as well; \langle \theta_12\rangle reaches at least 7 significant digits using a multipole expansion approach. Our results provide a precise reference for future research.