In view of late-time cosmic acceleration, a dark energy cosmological model is revisited wherein Einstein's cosmological constant is considered as a candidate of dark energy. Exact solution of Einstein field equations (EFEs) is derived in a homogeneous isotropic background in classical general relativity. The solution procedure is adopted, in a model independent way (or the cosmological parametrization). A simple parametrization of the Hubble parameter (H) as a function of cosmic time 't' is considered which produces an exponential type of evolution of the scale factor (a) and also shows a negative value of deceleration parameter at the present time with a signature flip from early deceleration to late acceleration. Cosmological dynamics of the model obtained have been discussed illustratively for different phases of the evolution of the universe. The evolution of different cosmological parameters are shown graphically for flat and closed cases of Friedmann-Lemaitre-Robertson-Walker (FLRW) space-time for the presented model (open case is incompatible to the present scenario). We have also constrained our model parameters with the updated (36 points) observational Hubble dataset.PACS numbers: 04.50.-h, 98.80.-k.

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A cosmological model in which the universe has its critical density and gravitational constants generalized as coupling scalars in Einstein's theory is considered. A general method of solving the field equations is given. An exact solution for matter distribution in cosmological models satisfying 𝐺 = 𝐺0(𝑅/𝑅0) 𝑛 is presented. Corresponding physical interpretations of the cosmological solutions are also discussed.

We consider cosmology with the gravitational and cosmological constants generalized as coupling scalars in Einstein's theory. A general method of solving the field equations is given. We study here the exact solutions for negative pressure models satisfying G = G 0 (R/R 0 ) n .

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