"The final goal of this proposal is to develop an SPM technique which is capable of identifying the type of atom which is under the tip while tunneling. The idea is to exploit the recent success in detection the hyperfine coupling between electron and nuclear spins on the surface and to detect the hyperfine coupling between the electron spin on the tip and a nuclear spin on the surface.ESN-STM is an emerging technique that is capable of single spin detection through modulation at the Larmor frequency of the tunneling current. Recently preliminary studies have shown that using ESN-STM for chemical contrast is a feasible and realistic goal. To achieve this goal, several improvements to the technique are necessary. To this end, we propose to develop and study four advanced ESN-STM setups: 1) at ambient conditions, 2) at ultra-high vacuum (UHV), 3) at low temperature (LT) and 4) LT-UHV. Each of these setups has its own particular advantage.We shall improve the rf recovery system, the spectroscopic analysis and we shall use magnetic tips and quadrature detection. The spectroscopic parameters that we will use are the g factor and hyperfine tensors and the longitudinal and transverse relaxation times. With the new technique, the chemical identity of the spin centers, the surrounding nuclei, the viscosity, the oxidation state and the motion of atoms and molecules etc can be revealed on the single atom and single molecule levels. The spectral parameters will be sensitive to the local environment. This local information is normally averaged out in macroscopic spectroscopy.The (expected) successful improvement of ESN-STM will provide the SME a market for a new technique of studying paramagnetic species on the surface. Yet, a full success of the project in developing an SPM technique with atom identification capability will result in a huge market for a new nano-chemical analysis tool."