Where die you search for it? Eventually using several databases would be helpful. However, the XPS peaks on NIST for Cu in Cu(OH)2 and CuCl2 are rather similar, so it will be hard to differentiate anyway.

Assuming you could differentiate, it depends what the crystal structure looks like: if all Cu ions are coordinated by an identical number of respective counterions, you should get one signal. If they have different coordinations, e.g. some are only coordinated by OH- the signal might show some splitting, but, as stated above, I would expect that to be very small.

What could happen more likely is that the signal differentiates between surface and bulk species.

The XPS spectrum of Atacamite can be found in the Elsevier book, "Handbook of Mineral Spectroscopy Volume 1 - XPS"

They report 3 oxygen peaks at 529.9, 531.7 and 533.2 eV which they assign as Cu-oxide, hydroxide and organic O-C fragments respectively. Their Cl 2p3/2 value is reported as 198.4 eV.

Dear Jinuk Gwon

To complement the analysis of oxygen species in your XPS experiment, I recommend to take a look at this article:

Article Systematic XPS Studies of Metal Oxides, Hydroxides and Peroxides

They discuss the different energy values for several oxygen species, including lattice oxygen (O{2-}), hydroxyl oxygen (OH-) and a less charged oxygen that occurs to compensate defects and charge deficiencies in the lattice (O-). The existence of the "less charged" species occur when doping the material or perform the heat treatment at reductive atmosphere.