ON ABSORPTION SPECTRA OP ORGANIC COMPOUNDS. 237 



in this process energy must be evolved. It was not possible previously to deter- 

 mine the amount of energy lost by each molecule in this process, but the theory 

 of elementary and molecular quanta put forward now enables this to be done 

 with accuracy. It was shown above that a freshly synthesised molecule is 

 characterised by a definite molecular quantum, and hence by a specified frequency 

 in the short wave infra-red, which has been called the infra-red fundamental 

 frequency. When a freshly synthesised molecule loses energy as a whole it 

 must do so in ouanta at the infra-red fundamental, and thus it would follow 

 that, -when the external force fields of the component atoms of a freshly syn- 

 thesised molecule condense together to form the molecular force field, the 

 svstem loses energy in quanta at the infra-red fundamental of that molecule. 

 Clearly, the molecule itself will not suffer anv loss of individuality as far as 

 its characteristic frequencies are concerned. None of the deductions from the 

 concention of elementary and molecular quanta made above will be contra- 

 dicted, and the only cliange accompanying the formation of the molecular force 

 field will be the endowment of the system with an additional molecular frequency 

 which is an exact multiple of the infra-red fundamental. Let it be supposed 

 that in the formation of its molecular force field a given molecule loses one 

 molecular quantum at the infra-red fundamental. If the freshly synthesised 

 molecule were allowed to absorb one quantum at the infra-red fundamental it 

 would become endowed with certain properties. If now it is required to bring 

 the molecule with its molecular force field established by the loss of one quantum 

 into this physical state it will be necessary to supply it with energy equal to 

 two energy quanta at the infra-red fundamental. There can be no reason against 

 the molecule and its force field absorbing both these quanta simultaneously, 

 and therefore it may be concluded that the system of molecule and force field 

 becomes endowed with a new and additional frequency which is exactly twice 

 the infra-red fundamental. Similarly, it follows that, if the force-field con- 

 densation proceeds to the extent defined by the loss of two molecular quanta at 

 the infra-red fundamental, the molecule and its force field will be endowed with 

 a new and additional frequency which is exactly three times the infra-red 

 fundamental. Generally, if the infra-red fundamental of a freshly .synthesised 

 molecule be denoted by M, and if in the formation of the force field x quanta 

 are evolved at that frequencv. the system will be characterised by two molecular 

 frequencies, namely M and M(.r-f 1). Since the external atomic fields are bound 

 to undergo a certain amount of condensation, it is evident that the molecule 

 mu.st exist in one of a number of possible phases, each molecular phase being 

 defined by the number of molecular quanta lost in the force-field condensation 

 and characterised by a specific frequency which is an exact multiple of the 

 infra-red fundamental. 



The initial assumption was made that the chemical reactivity of atoms is due 

 to the attraction exerted by their electromagnetic fields. As the result of this 

 attraction the atoms form an addition complex which constitutes the first stage 

 in the reaction between them, the second stage being the joint loss of equal 

 amounts of energy by all the atoms wherebv the freshly synthesised molecule 

 is formed with its infra-red fundamental. Similarly the reactivity of molecules 

 will be a function of their force fields, and the first stasre of any reaction between 

 two or more molecules will be the formation of the addition complex due to the 

 attraction between their respective force fields. It follows, therefore, that the 

 reactivity of a molecule will depend on the molecular phase in which it exists, 

 and, further, the £;reater the extent to which the condensation in the molecular 

 force field has taken place the smaller will be the reactivity. The phase in 

 which a molecule exists is governed by the nature of the external force fields 

 of its atoms. The more equally balanced these are the greater will be the 

 condensation that takes place between them. The particular phase assumed by 

 a molecule will depend on the external conditions, such as temperature, nature 

 of solvent, &c. 



The experimental evidence in favour of the existence of these molecular 

 phases is exceedingly strong. It is not possible to give here a detailed account 

 of this evidence, but two or three of the most striking observations may be 

 pip'-it'onod. F"r instance, it is common knowledge that substances which nos- 

 8686 very »niall reactivity are characterised by molecular frecjuencies whicji are 



