  In this work, the effect of uniaxial pressure along the c axis on the
electronic structure of the HTSC cuprate La2-xSrxCuO4 is investigated at the
doping levels x = 0.1, 0.15, 0.25. The GTB method within the five-band p-d
model framework is used to describe the electron system. The uniaxial
compression leads to a significant reconstruction of the electronic structure
and a change in the character of low-energy quasiparticle excitations: a large
contribution of a1g symmetry orbitals appears at the top of the valence band.
The crossover between the local Zhang-Rice singlet and the Emery-Reiter triplet
was found at the pressure Pc = 15.1 GPa. The characteristic changes in the
electronic structure under pressure occur abruptly as a result of the
crossover. In particular, the top of the valence band displaces to the region
around the k-point (pi,0), the Fermi contour transforms to the four pockets
around (0,0),(2pi,0),(0,2pi),(2pi,2pi) and the one contour around (pi,pi).
