Dark energy models due to a slowly evolving scalar ( quintessence ) field \phi are studied for various potentials V ( \phi ) in a universe with negative curvature .
The potentials differ in whether they possess a minimum at \phi = 0 or are monotonically declining , i. e. have a minimum at infinity .
The angular power spectrum C _ { l } of the cosmic microwave background ( CMB ) as well as the magnitude-redshift relation m _ { \text { B } } ( z ) of the type Ia supernovae are compared with the quintessence models .
It is demonstrated that some of the models with \Omega _ { \text { tot } } \simeq 0.85 \dots 0.9 are in agreement with the observations , i. e. possess acoustic peaks in the angular power spectrum of the CMB anisotropy as observed experimentally , and yield a magnitude-redshift relation in agreement with the data .
Furthermore , it is found that the power spectrum P ( k ) of the large-scale structure ( LSS ) agrees with the observations too .