Based on molecular nanoelectronic knowledge, field-effect molecular electronic devices can be designed for use in nano-circuits. Therefore, in this study, a candidate field-effect molecular switch (isolated, M, and non-isolated, Au-M-Au/Au4-M-Au4, molecular systems) is studied, using density function/pseudopotential model (DFT/LANL2DZ). This molecular switch's switching mechanism (ON/OFF) we performed by applying an external electric field-effect. In this regard, some computational studies related to this molecular switch's electronic/vibrational transfer properties were investigated. Also, used from the quantum theory of atoms in the molecule (QTAIM), Landauer's theory (LT), and energy/charge transfer mechanisms were used at the atomic scale to predict this molecular switch's voltage-current (IV) behavior. Analysis of these results showed that when the intensity of the applied electric field increases to 0.008 au, the molecular switch is in the ON state. In addition, the role of gold electrodes on some of the electronic/vibrational properties of this molecular switch was investigated. Analysis of the results showed that gold electrodes play an essential role in the local distribution of charge and intramolecular energy and, consequently, the I/V diagram of this molecular switch. It is expected that such quantum-based research (without using numerical methods such as Green's function methods) could open new horizons in the quantum study of molecular parts at the atomic-intramolecular scale.