Fully Anharmonic Vibrational Resonance Raman Spectrum of Diatomic Systems

Autor(es)

Costa, Gustavo J. ^[1] ; Borin, Antonio C. ^[2] ; Custodio, Rogerio ^[3] ; Vidal, Luciano N. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Tecnol Fed Parana, Dept Acad Quim & Biol, Av Dept Heitor de Alencar Furtado 5000, BR-81280340 Curitiba, PR - Brazil

^[2] Univ Sao Paulo, NAP Photo Tech USP Consortium Photochem Technol, Inst Chem, Dept Fundamental Chem, Av Prof Lineu Prestes 748, BR-05508000 Sao Paulo, SP - Brazil

^[3] Univ Estadual Campinas, Inst Quim, R Josue de Castro 126, BR-13083970 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF CHEMICAL THEORY AND COMPUTATION; v. 14, n. 2, p. 843-855, FEB 2018.
• Citações Web of Science: 0

Resumo

A study is presented on the resonance Raman (RR) spectrum based on fully anharmonic wave functions and energies obtained from ab initio multireference potential energy curves of diatomic systems. The vibrational problem is numerically solved using a variational stochastic method or the Cooley-Numerov method, as implemented in Le Roy's LEVEL program. Anharmonic Franck-Condon and Herzberg-Teller integrals are numerically evaluated, and the RR polarizability is calculated within the time-independent framework of the RR theory. At the harmonic level, the differential cross sections show faster convergence with respect to the number of intermediate vibrational states than what is obtained from anharmonic wave functions. Twice as many intermediate states are required to achieve the same convergence in the RR intensities as observed within the harmonic model. The anharmonic spectra evaluated for H-2, C-2, and O-2 molecules show that RR intensities are strongly affected by anharmonic effects. They differ from their harmonic counterparts not only in the position of the peaks but also in the absolute and relative intensities. (AU)

• Processo FAPESP: 13/08293-7 - CECC - Centro de Engenharia e Ciências Computacionais
• Beneficiário: Munir Salomao Skaf
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 17/11485-6 - Desenvolvimentos computacionais e teóricos baseados em métodos ab initio e na Teoria do Funcional de Densidade
• Beneficiário: Rogério Custodio
• Modalidade de apoio: Auxílio à Pesquisa - Regular