We utilize a nonvariational ansatz as the perturbative term to study the quadratic Stark effect of hydrogenic systems in a fractional-dimensional space. Applying a Dalgarno-Lewis-type technique, the ansatz is used to derive an analytical expression for the Stark shifts in quantum wells. Estimates of the energy shifts of negatively charged excitons are in good agreement with recent experimental results, and provide qualitative explanations for their behavior in a weak external electric field. The model is extended to study the Stark shifts of positively charged excitons and biexcitons in quantum wells.

• Received 24 March 1997

DOI:https://doi.org/10.1103/PhysRevB.56.4665