Probing electron-phonon coupling in high-Tc superconductors by site-selective isotope substitution.

We consider changes in the electron-phonon coupling in high- T _c cuprates caused by site-selective oxygen isotope substitution. Contrary to the total substitution, the site-selective replacement influences the coupling constant for each phonon mode due to the induced changes in the phonon eigenvectors. The relative changes for some modes can be larger than 100%. The measured properties sensitive to these changes are discussed. [ABSTRACT FROM AUTHOR]