We investigate the evolution of matter density perturbations and some properties of the peculiar velocity field for a special class of exponential potentials in a scalar field model for quintessence , for which a general exact solution is known .
The data from the 2-degree Field Galaxy Redshift Survey ( 2dFGRS ) suggest a value of the today pressureless matter density \Omega _ { { M 0 } } = 0.18 { \pm } 0.05 .

KEYWORDS : cosmology : theory - cosmology : quintessence - large-scale structure of Universe