Excited state quantum phase transitions in the bending spectra of molecules
Journal of Quantitative Spectroscopy and Radiative Transfer
© 2020 The Author(s)We present an extension of the Hamiltonian of the two dimensional limit of the vibron model to encompass all possible interactions up to four-body operators. We apply this Hamiltonian to the modeling of the bending spectrum of four molecules: HNC, H2S, Si2C, and NCNCS. The selected molecular species include linear, bent, and nonrigid equilibrium structures, proving the versatility of the algebraic approach which allows for the consideration of utterly different physical cases within a single Hamiltonian and a general formalism. For each case we compute predicted bending energies and wave functions, that we use to depict the associated quantum monodromy diagram, Birge-Sponer plot, and participation ratio. In nonrigid cases, we also show the bending energy functional obtained using the coherent –or intrinsic– state formalism.
Algebraic vibron model, Bending rovibrational structure, Bent molecules, Excited state quantum phase transition, Linear molecules, Nonrigid molecules