INTERMOLECULAR FORCES AND INTERACTION ENERGY 



225 



tron pairs), and a new vibrational frequency v^, this being dependent on 

 the mass and charge of the electron and the polarizability of the molecule: 



which for the interaction between identical molecules reduces to: 



(6-39) 



(6-40) 



The quantity hv^ is no longer the ionization energy. Values of v^ and Z 

 for some common molecules are given in Table 6-6. Actually this treatment 

 still does not provide energy values sufficiently high and further improve- 

 ment may be made by using another frequency v,. which is obtained 

 from dispersion data and is related to v^ by the equation i\. = y s v/. 





(6-41) 



Table 6-6 



Optical Constants for Simple Molecules " 



" Taken in part from Moelwyn-Hughes (1957, p. 373) and includes only molecules 

 of possible interest in biological interactions. 



