1) With the close association of molecules, there arise clusters 

 which have a great number of possible modes of vibration. For each mode 

 there exists a frequency spectrum in a different frequency range. It's 

 quite possible that there are enough different size clusters to completely 

 cover the infrared region. 



2) As mentioned above, water vapor has a rotational spectrum spread 

 out through the infrared. In the liquid it is probable that there is no 

 free rotation for the water molecule, but only hindered rotation. Whether 

 free or hindered, however, each rotational state will be split by any 

 electric field present, the amount of splitting depending on the strength 

 of the field. Because of the fact that water possesses a dipole moment 



of 1.87 Debye, rather strong fields exist at each water molecule. An 

 estimate of this field can be obtained from the formula 



E --i^ = 1.87x10"-^^ /(2xl0'^)^ = 2.5x10^ e.s.u. 

 r 

 or about 10 volts/cm. This huge field depends critically on the positions 

 of neighboring molecules and therefore fluctuates considerably. In effect 

 the fluctuation smears out each rotational level and could well account 

 for the lack of a window. 



It seems to the author that these two reasons are extremely strong 

 arguments against the purchase of additional and much more expensive infrared 

 detectors of greater sensitivity than the Eppfey thermopile^ Some work 

 remains to be done in this field dealing with the problems of the effect of 

 association of molecules on radiation and the measuring of the electric 

 fields present in water. However, these topics will be covered in a future 

 report. 



-14- 



