Impact of nonconvergence and various approximations of the partition function on the molecular column densities in the interstellar medium

This work is partly supported by CMST COST Action CM1401 Our Astro-Chemical History and CMST COST Action CM1405 MOLIM. work of C.F. is supported by the French National Research Agency in the framework of the Investissements d'Avenir program (ANR-15-IDEX-02), through the funding of the Origin of Life project of the Universite Grenoble-Alpes. C.C. and C.F. acknowledge funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme, for the Project The Dawn of Organic Chemistry (DOC), grant agreement No 741002. I.K. would like to thank the French programme of Chimie Interstellaire PCMI. C.F. and D.F. acknowledge support from the Italian Ministry of Education, Universities and Research, project SIR (RBSI14ZRHR). E.A.B. acknowledges support from NSF (AST-1514670) and NASA (NNX16AB48G). M.C. acknowledges the financial support from FIS2014-53448-C2-2-P (MINECO, Spain), from the Centro de Estudios Avanzados de Fisica, Matematicas y Computacion (CEAFMC) of the University of Huelva and from the Consejeria de Conocimiento, Investigacion y Universidad, Junta de Andalucia and European Regional Development Fund (ERDF), ref. SOMM17/6105/UGR. authors acknowledge the referee for his/her valuable comments.