We perform non-LTE calculations of lithium in late-type stars for a wide range of stellar parameters , including quantum mechanical cross-sections for collisions with neutral hydrogen and the negative hydrogen ion .
Non-LTE abundance corrections for the lithium resonance line at 670.7 nm and the subordinate line at 610.3 nm , are calculated using 1D MARCS model atmospheres spanning a grid T _ { eff } = [ 4000 , 8000 ] K , \log { g } = [ 1.0 , 5.0 ] , and [ Fe / H ] = [ 0.0 , -3.0 ] , for lithium abundances in the range A ( Li ) = [ -0.3 , 4.2 ] .
The competing effects of ultraviolet over-ionization and photon losses in the resonance line govern the behaviour of the non-LTE effects with stellar parameters and lithium abundance .
The size and sign of the non-LTE abundance corrections vary significantly over the grid for the 670.7 nm line , but are typically positive and below 0.15 dex for the 610.3 nm , line .
The new collisional data play a significant role in determining the abundance corrections .