Photoassociation measurements to evaluate collisional shifts in strontium and prospects for clock spectroscopy with ytterbium molecules

We report on a photoassociation approach to determine the scattering lengths for 1 So- 3 Po and 3 Po- 3 Po cold collisions. Positions of molecular states, connected with asymptotes of 1 So+ 3 S1 and 3 Po+ 3 S1 states could be determined using a tunable 679 nm laser and atoms trapped in an optical lattice. This approach allows an indirect calculation (without direct probing of 1 S0- 3 P0 molecular state) of the effect of cold collisions on an optical atomic clock operation. We also propose to realize a molecular clock with bosonic ytterbium molecules.