Investigation Nonlinear Properties (First and Second Hyperpolarizabilities) of The Nitro-thieno [3,2-b] thiophene -fullerene (C20) Molecule. Baghdad Sci.J [Internet]. 2024 Jun. 1 [cited 2025 Jan. 22];21(6):2146. Available from: https://bsj.uobaghdad.edu.iq/index.php/BSJ/article/view/8659