Exploration of nonlinear optical behavior in asymmetric dithieno [3,2b:2′,3′d] pyrrole based push pull constrain: a theoretical approach - khalid, Muhammad; Hanif, Saira; Ahmed, Sarfraz; Asghar, Muhammad Adnan; Imran, Muhammad; Braga, Ataualpa Albert Carmo; Ojha, Suvash Chandra (Journal of Saudi Chemical Society, 2023)