First theoretical probe for efficient enhancement of optical nonlinearity via structural modifications into phenylene based D–π–A configured molecules - Khalid, Muhammad; Naz, Salma; Mahmood, Khalid; Hussain, Shabbir; Braga, Ataualpa Albert Carmo; Hussain, Riaz; Ragab, Ahmed H; Al-Mhyawi, Saedah R. (RSC Advances, 2022)