TY - JOUR
T1 - The electronic excited states of dichloromethane in the 5.8-10.8 eV energy range investigated by experimental and theoretical methods
AU - Lange, Emanuele
AU - Jones, Nykola C.
AU - Hoffmann, S. V.
AU - Lozano, Ana Isabel
AU - Kumar, Sarvesh
AU - Homem, Manoel Gustavo Petrucelli
AU - Śmiałek, Małgorzata A.
AU - Duflot, D.
AU - Brunger, Michael J.
AU - Limão-Vieira, Paulo
N1 - Funding Information:
E.L. acknowledges the Brazilian Agency Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and the Science Without Borders Programme for opportunities to study abroad.
S.K. acknowledges the Portuguese National Funding Agency FCT through Researc Grant PD/BD/142831/2018, and, together with A.I.L. and P.L.V., the Research Grants CEFITEC (UIDB/00068/2020) and PTDC/FIS-AQM/31281/2017.
This work was also supported by the Radiation Biology and Biophysics Doctoral Training Programme (RaBBiT, PD/00193/2012); UCIBIO (UIDB/04378/2020). The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 226716. DD acknowledges the support of the OVERSEE and CAPPA grants, managed by the Agence Nationale de la Recherche under the frame programs Investissements dAvenir ANR-10-LABX-005 and I-SITE ULNE/ANR-16-IDEX-0004 ULNE, respectively. DD acknowledges the support of the OVERSEE and CAPPA grants, managed by the Agence Nationale de la Recherche under the frame programs Investissements d'Avenir ANR-10-LABX-005 and I-SITE ULNE/ANR-16-IDEX-0004 ULNE, respectively. D.D. also thanks the Région Hauts de France, the Ministère de l'Enseignement Supérieur et de la Recherche (CPER Climibio) and the European Fund for Regional Economic Development for their support. This work used HPC resources from GENCI-TGCC (Grant No. 2019-A0010806820) and the Centre de Ressources Informatiques (CRI) of the Université de Lille. Partial financial support from the Australian Research Council through grant DP180101655 is also acknowledged.
PY - 2020/9
Y1 - 2020/9
N2 - We present a comprehensive experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectrum of dichloromethane, CH2Cl2, with absolute cross sections determined for the full 5.8–10.8 eV energy-range. The calculations on the vertical excitation energies and oscillator strengths were performed using the equation-of-motion coupled cluster method, restricted to the single and double excitations level (EOM-CCSD), and were used to help analyse the valence and Rydberg structures in the photoabsorption spectrum. The present spectrum additionally reveals several new features not previously reported in the literature, with particular reference to the valence σCCl*(10a1)←nCl(7b2)(11B2←X˜1A1) and (σCCl*(10a1)←nCl(9a1)+σCH*(11a1)←nCl(7b2))(11A1←X˜1A1) transitions at 7.519 and 7.793 eV. A vibrational progression of the CCl2 symmetric stretching, ν3′, and CCl2 scissoring, v4′(a1), modes have also been assigned for the first time in the 7.4–8.6 eV energy range. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of dichloromethane in the Earth's atmosphere (0–50 km). Potential energy curves as a function of the C–Cl coordinate, for the four lowest-lying excited A′ and A″ electronic states, have additionally been calculated at the EOM-CCSD level of theory.
AB - We present a comprehensive experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectrum of dichloromethane, CH2Cl2, with absolute cross sections determined for the full 5.8–10.8 eV energy-range. The calculations on the vertical excitation energies and oscillator strengths were performed using the equation-of-motion coupled cluster method, restricted to the single and double excitations level (EOM-CCSD), and were used to help analyse the valence and Rydberg structures in the photoabsorption spectrum. The present spectrum additionally reveals several new features not previously reported in the literature, with particular reference to the valence σCCl*(10a1)←nCl(7b2)(11B2←X˜1A1) and (σCCl*(10a1)←nCl(9a1)+σCH*(11a1)←nCl(7b2))(11A1←X˜1A1) transitions at 7.519 and 7.793 eV. A vibrational progression of the CCl2 symmetric stretching, ν3′, and CCl2 scissoring, v4′(a1), modes have also been assigned for the first time in the 7.4–8.6 eV energy range. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of dichloromethane in the Earth's atmosphere (0–50 km). Potential energy curves as a function of the C–Cl coordinate, for the four lowest-lying excited A′ and A″ electronic states, have additionally been calculated at the EOM-CCSD level of theory.
KW - Cross-sections
KW - Dichloromethane
KW - Potential energy curves
KW - Rydberg states
KW - Theoretical calculations
UR - http://www.scopus.com/inward/record.url?scp=85086825019&partnerID=8YFLogxK
U2 - 10.1016/j.jqsrt.2020.107172
DO - 10.1016/j.jqsrt.2020.107172
M3 - Article
AN - SCOPUS:85086825019
SN - 0022-4073
VL - 253
JO - Journal of Quantitative Spectroscopy and Radiative Transfer
JF - Journal of Quantitative Spectroscopy and Radiative Transfer
M1 - 107172
ER -