Something like an adapted AFM system may be able to give you a value for this; either manipulating the cantilever to move one surface away from another, or 'doping' the cantilever with one molecule and measuring the attraction force as it approaches the other. That said, this is far from trivial. Maybe someone with experience in AFM/cell adhesion studies may be able to provide more details.

Dear Mohammad. This is a complicated question. Nevertheless, you can read the book entitled "Intermolecular and surface forces" by J. Israelachvili, Academic press. There is a complete chapter dedicated to this topic.

thanks Jerome and Barry for your answer. Jerome, is this book available in online?

Yes. Here: http://www.sciencedirect.com/science/book/9780123751829#ancp1

To calculate the existence of these type of interactions You can use some tools based on Bader analysis and reduced density gradient value (RDG) for example NCIPlot. This tool will also allow You to estimate the electron density associated with weak Interactions. I recommend You to read Julia Contreras-García publications e.g. J. Chem. Theory Comput., 2011, 7 (3), pp 625–632. If You need help with calculations I will help You. How Your system exactly look like?

Calculations can be done using a level of theory that includes electronic correlation and drawing a potential energy surface curve. AT semi empirical level one can use atom atom pair potentials.

Experimentally, the atomic force microscopes are in fact using van der Waals forces, that could be therefore measured (though with rather complicated experiments).

You can use AIM (Atoms in molecules) approach developed by Bader, in which it will calculated elctroc density for your given molecule, and after taking the laplacian of rho(electron density) , we can easily decide whether its a covalent or ionic or H-Bond or Van Der Waals bond.