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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Quantum chemical intensity determinations of overlapped gas phase infrared bands

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Author(s):
Duarte, Leonardo J. [1] ; Richter, Wagner E. [2] ; Silva, Arnaldo F. [3, 4] ; Bruns, Roy E. [1]
Total Authors: 4
Affiliation:
[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
Total Affiliations: 4
Document type: Journal article
Source: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY; v. 230, APR 5 2020.
Web of Science Citations: 0
Abstract

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)

FAPESP's process: 18/08861-9 - Application of the QTAIM / CCTDP model and machine learning for the forecast of chemical reactivities
Grantee:Roy Edward Bruns
Support Opportunities: Regular Research Grants
FAPESP's process: 18/24844-7 - Using atomic polar tensors and QCT parameters to train a machine learning model and predict Hammett constants.
Grantee:Leonardo José Duarte
Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)