The oxy-hemocyanin exhibits a resonance Raman signal at 744 cm-1 for 16O-16O stretch, following its excitation at 575nm. The value of the 18O-18O stretch for an 18O2 substituted oxy-hemocyanin, and the origin of the absorption band, are
1
702 cm-1 and O2- → Cu(II) charge transfer
2
702 cm-1 and O22- → Cu(II) charge transfer
3
664 cm-1 and O2- → Cu(II) charge transfer
4
792 cm-1 and O22- → Cu(II) charge transfer