In the well-known Meyer-Miller (MM) mapping model (frequently, it is referred to as the Meyer-Miller-Stock-Thoss model ), the quantum Hamiltonian containing N coupled electronic states is mapped into the Hamiltonian containing N coupled harmonic oscillators. This mapping procedure is founded on Schwinger's theory of angular momentum . Among different MM mapping schemes, the symmetrical quasi-classical (SQC) variant provides an effective way to simulate nonadiabatic processes . Several benchmark calculations have shown that the SQC/MM method gives a reasonably accurate description at affordable computational costs . In the SQC/MM simulations, the triangle windowing protocol and the adjusted γ correction are always recommended . After convincing demonstrations of performing mapping dynamics in on-thefly , the SQC/MM and other mapping approaches have been successfully applied to realistic polyatomic systems .