Excited state quantum phase transitions in the bending spectra of molecules Khalouf Rivera, Jamil Pérez Bernal, Francisco Carvajal Zaera, Miguel Nonrigid molecules Linear molecules Excited state quantum phase transition Bent molecules Bending rovibrational structure Algebraic vibron model We thank useful discussion with Profs. Francesco Iachello, Renato Lemus, and Georg Mellau. This project has received fund-ing from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 872081 and from the Spanish National Research, Development, and Innovation plan (RDI plan) under the project PID2019-104002GB-C21. This work has also been partially supported by the Consejeria de Conocimiento, Investigacion y Universidad, Junta de Andalucia and European Regional Development Fund (ERDF), ref. SOMM17/6105/UGR, by the Ministerio de Ciencia, Innovacion y Universidades (ref.COOPB20364), and by the Centro de Estudios Avanzados en Fisica, Matematicas y Computacion (CEAFMC) of the University of Huelva. JKR thanks support from the Youth Employment Initiative and the Youth Guarantee program supported by the European Social Fund. FPB and JKR thank the obtained support from the project UHU-1262561. Computing resources supporting this work were provided by the CEAFMC and Universidad de Huelva High Performance Computer (HPC@UHU) located in the Campus Universitario El Carmen and funded by FEDER/MINECO project UNHU-15CE-2848. 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 intrinsicstate formalism. 2021-05-26T08:25:44Z 2021-05-26T08:25:44Z 2020-11-18 info:eu-repo/semantics/article Jamil Khalouf-Rivera, Francisco Pérez-Bernal, Miguel Carvajal, Excited state quantum phase transitions in the bending spectra of molecules, Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 261, 2021, 107436, ISSN 0022-4073, [https://doi.org/10.1016/j.jqsrt.2020.107436] http://hdl.handle.net/10481/68733 10.1016/j.jqsrt.2020.107436 eng info:eu-repo/grantAgreement/EC/H2020/872081 http://creativecommons.org/licenses/by-nc-nd/3.0/es/ info:eu-repo/semantics/openAccess Atribución-NoComercial-SinDerivadas 3.0 España Elsevier