Quantum chemical intensity determinations of overlapped gas phase infrared bands

Autor(es)

Duarte, Leonardo J. ^[1] ; Richter, Wagner E. ^[2] ; Silva, Arnaldo F. ^{[3, 4]} ; Bruns, Roy E. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Inst Quim, CP 6154, BR-13083970 Campinas, SP - Brazil

^[2] Univ Tecnol Fed Parana, Dept Engn Quim, Campus Ponta Grossa, Av Monteiro Lobato S-N, BR-84016210 Jardim Carvalho - Brazil

^[3] Univ Manchester, Sch Chem, Oxford Rd, Manchester M13 9PL, Lancs - England

^[4] MIB, 131 Princess St, Manchester M1 7DN, Lancs - England

• Tipo de documento: Artigo Científico
• Fonte: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY; v. 230, APR 5 2020.
• Citações Web of Science: 0

Resumo

The largest source of experimental error in determining gas phase fundamental infrared intensities arises from the separation of overlapped bands. Quantum chemical calculations at the QCISD/cc-pVIZ and QCISD/aug-ccpVIZ levels were carried out on four simple hydrocarbons and the fluoro- and chloromethanes with the aim of accurate overlapped band separation. Fundamental vibrational intensity results were compared with individual empirical intensity estimates reported for overlapped band systems. Root mean square differences of 3.7 km mol(-1) are found between the experimental and QCISD/cc-pVIZ values for nine overlapped bands of the hydrocarbons and 11.8 km mol(-1) for the QCISEVaug-cc-pViZ values for 12 overlapped bands of the fluoro-and chloromethanes. These values correspond to 14% and 18% of the average hydrocarbon and halomethane intensity values. Previous experimental separation errors were estimated to be quite larger, between 20% and 50%. As quantum calculations are continuously being refined one can expect more accurate band separation results in the future. (C) 2020 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 18/08861-9 - Aplicação do modelo QTAIM / CCTDP e machine learning para a previsão de reatividades químicas
• Beneficiário: Roy Edward Bruns
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 18/24844-7 - Uso de tensores polares atômicos e parâmetros QCT para treinar um modelo de machine learning e prever constantes de Hammett
• Beneficiário: Leonardo José Duarte
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado Direto