Table 1: Raman shifts indicate good extent of isotopic substitution

From: A large iron isotope effect in SmFeAsO1 - xFx and Ba1 - xKxFe2As2

Table 1
  1. Shown are the Raman shifts of the Eg mode of oxygen (ωO) and the B1g mode of iron (ωFe) in the SmFeAsO1 - xFx (x = 0, 0.15) samples with natural abundance oxygen nO and 18O, and in the SmFeAsO1 - xFx (x = 0, 0.15) samples and Ba1 - xKxFe2As2 (x = 0, 0.4) samples with 54Fe and 56Fe, respectively. To calculate the 18O and 54Fe isotopic contents we assumed the Raman shift to be proportional to 1 - (16/M')1/2 for the substitution of 18O for nO and proportional to 1 - (55.93/M')1/2 for the substitution of 54Fe for 56Fe, respectively. For the calculation, we used the following molar masses M' for isotope exchange: 53.93 g for 54Fe and 55.93 g for 56Fe, and 16 g for nO and 18 g for 18O.