Factors of 18O/16O fractionation in corundum estimated from the calculation of isotopic shifts on vibration frequencies
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The β-factors of corundum were estimated on the basis of DFT calculations of vibrational frequency changes due to 16O–18O isotope substitution in a harmonic approximation using an all-electron Gaussian-type basis set and the B3LYP hybrid functional (the CRYSTAL program). Calculations were performed accounting for eight phonon wave vectors within the first Brillouin zone. The results are approximated by the relation 1000ln β crn = 9.19874x–0.12326x 2 + 0.00213x 3 (x = 106/T(K)2, 400 < T(K) < 1300), which can be used in isotope geochemical studies in combination with the known temperature effects on the β-factors of other phases.
Keywordsisotope geothermometry corundum fractionation factors
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- T. Chacko, D. R. Cole, and J. Horita, “Equilibrium oxygen, hydrogen and carbon isotope fractionation factors applicable to geologic systems,” in Stable Isotope Geochemistry, Ed. by J. W. Valley and D.R. Cole, Rev. Mineral. Geochem. 43 (1), 1–81 (2001).Google Scholar
- R. Dovesi, R. Orlando, A. Erba, C. M. Zicovich-Wilson, B. Civalleri, S. Casassa, L. Maschio, M. Ferrabone, M. De La Pierre, P. D’Arco, Y. Noel, M. Causa, M. Rerat, and B. Kirtman, “CRYSTAL14: A program for the ab initio investigation of crystalline solids,” Int. J. Quantum Chem. 114 (19), 1287–1326 (2014a).CrossRefGoogle Scholar
- R. Dovesi, V. R. Saunders, C. Roetti, R. Orlando, C. M. Zicovich-Wilson, F. Pascale, B. Civalleri, K. Doll, N. M. Harrison, I. J. Bush, P. D’Arco, M. Llunell, M. Causà, and Y. Noël, “CRYSTAL14 User’s Manual,” (University of Torino, Torino, 2014b).Google Scholar
- V. B. Polyakov and V. I. Ustinov, “Isotope equilibrium constants (β18O-factors) of corundum,” Geochem. Int. 35 (10), 897–903 (1997).Google Scholar