Modern theoretical methods used in study of molecular structure, bonding, and reactivity. Concepts and practical applications. Semiempirical, ab initio, and density functional calculations of molecular electronic structure. Theoretical determination of molecular structure and spectra; relationship to experimental techniques. Molecular mechanics. Structure determination of large systems. Study of molecular properties and reactivity by theoretical methods. Computational tools for theoretical determination and lab for hands-on experience. Critical assessment of reliability of methods and theoretical work in literature.