Computational methodology study of the optical and thermochemical properties of a molecular photoswitch

Stine T Olsen; Jonas Elm; Freja Eilsø Storm; Aske Nørskov Gejl; Anne S Hansen; Mia Harring Hansen; Jens Rix Nikolajsen; Mogens Brøndsted Nielsen; Henrik G Kjaergaard; Kurt V Mikkelsen

doi:10.1021/jp510678u

Computational methodology study of the optical and thermochemical properties of a molecular photoswitch

J Phys Chem A. 2015 Feb 5;119(5):896-904. doi: 10.1021/jp510678u. Epub 2015 Jan 21.

Authors

Stine T Olsen¹, Jonas Elm, Freja Eilsø Storm, Aske Nørskov Gejl, Anne S Hansen, Mia Harring Hansen, Jens Rix Nikolajsen, Mogens Brøndsted Nielsen, Henrik G Kjaergaard, Kurt V Mikkelsen

Affiliation

¹ Department of Chemistry, H. C. Ørsted Institute, University of Copenhagen , Universitetsparken 5, DK-2100 Copenhagen, Denmark.

PMID: 25569127
DOI: 10.1021/jp510678u

Abstract

We assess how the utilization of different DFT functionals for obtaining the equilibrium geometries and vibrational frequencies affect the description of the thermochemistry and subsequent calculation of the optical properties of a dihydroazulene-vinylheptafulvene photoswitch. The assessment covers nine popular DFT functionals (BLYP, B3LYP, CAM-B3LYP, M06-L, M06, M06-2X, PBE, PBE0, and ωB97X-D) in conjugation with five different Pople style basis sets (6-31+G(d), 6-31++G(d,p), 6-311+G(d), 6-311++G(d,p), and 6-311++G(3df,3pd)). It is identified that only CAM-B3LYP, M06-2X, and PBE0 are able to quantitatively describe the correct trends in the thermochemical properties. The subsequent calculation of the optical properties using the CAM-B3LYP functional shows that there is little difference in whether the CAM-B3LYP, M06-2X, or PBE0 functionals have been used to calculate the equilibrium geometries. Utilizing the identified functionals, we investigate how the number of electron withdrawing cyano substituents influence the thermochemistry and optical properties of the molecular photoswitch.