Vibrational resonance in bichromatically excited diatomic molecules in a shifted molecular potential

Abamba, O. G. and Kolebaje, O. T. and Vincent, Uchechukwu E. and McClintock, Peter V. E. (2024) Vibrational resonance in bichromatically excited diatomic molecules in a shifted molecular potential. Physical Review E. ISSN 1539-3755 (Unpublished)

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Abstract

For bichromatically excited diatomic molecules modelled in a shifted Tietz-Wei molecular potential, we demonstrate the occurrence of vibrational resonance (VR) when a saddle-node (SN-)bifurcation takes place, and its non-occurrence in the absence of an SN-bifurcation. We have examined the VR phenomenon and its connection with SN-bifurcation for eight diatomic molecules, namely, H2, N2, Cl2, I2, O2, HF, CO, and NO, consisting of homogeneous, heterogenous and halogen molecules. We demonstrate that each of them vibrates at a distinct resonant frequency but with a spread in frequency. The high-frequency amplitude at which VR occurs corresponds to the SN-bifurcation point. We validate our analytic results by numerical simulations, and show that the homonuclear halogens respond only weakly to bichromatic fields, which may perhaps be linked to their absence of SN-bifurcation.