A local-density approximation for the exchange energy functional for   excited states : the band gap problem
  We present excited states density functional theory (DFT) to calculate band gap for semiconductors and insulators. For the excited states exchange-correlation functional, we use a simple local density approximation (LDA) like functional and it gives the result which is very closed to experimental results. The linear muffin-tin potential is used to solve the self consistent Kohn-Sham equation 
Moshiour Rahaman, Shreemoyee Ganguly, Prasanjit Samal, Manoj Kumar   Harbola, Tanusri Saha-Dasgupta, Abhijit Mookerjee