At all stages of their evolution, low-and intermediate-mass stars
exhibit the signatures of complex physical processes that require
challenging modelling beyond canonical (or standard) stellar theory
(by canonical we refer to the modelling of non-rotating, non-magnetic
stars, in which convection is the only mechanism that drives mixing in
stellar interiors). In particular, spectroscopic observations show
clear signatures of extra-mixing on the upper Red Giant Branch. To
explain these abundances anomalies, Charbonnel & Zahn (2007)
identified thermohaline mixing as the dominating process that governs
the photospheric composition of low-mass bright giant stars. We
present the predictions of our stellar models computed with the code
STAREVOL, taking into account this mechanism together with rotational
mixing. We discuss the effects of these processes on the chemical
properties of stars (Charbonnel & Lagarde 2010), and on the
corresponding yields for 3He in the context of the so-called the "3He
problem".