116 



RADIATION BIOLOGY 



Table 2-4. tt-Electron Densities in Porphin and Tetrahydroporphin" 



(One-electron Approximation) 



Position 



Porphyrin 

 polarization 



Chlorin 

 polarization 



States 



(C/x) 



Q. 



Qy 



By 



B. 



Porphin 



Tetrahydroporphin 



Rings on H-H 



axis 

 1,2,5,6 



Ni, Niii 



Bi, Bi', 1 

 Bin, Bin', J 



a,/3,7,5 



Rings off H-H 

 axis : 

 Bii, Bit', 1 

 Biv, Biv J 



Nil, Niv 

 3,4,7,8 



Ground 



state 



Excitation 



n-hsg biu-bia au-hzg biu-b 



1.114 

 1.276 



1.093 

 1.062 



1.056 



1.075 

 (1.000) 



1.180 

 1.276 



1.121 

 1.160 



1.059 



1.186 

 (1.000) 



1.180 



iTisT 



1.121 

 1.035 



1.059 



1.061 

 1. 000) 



1.133 

 1.276 



TM7 

 1.147 



0.951 



1.186 

 (1.000) 



^29 



1.118 

 1.241 



1.107 

 ITOTO 



1.169 



0:950 

 (1.000 



ttu-bt 



1.071 

 1.366 



TT023 

 1.122 



1.061 



1.075 

 (1.000) 



" The following symbols are used in the table: 



Ni, the nitrogen on ring I; Bi, either branch carbon of ring 1; etc. 



A bar over the density values indicates considerable loss of electrons in the excited 

 state; a bar under th(> values, considerable gain. 



Figures in parentheses in the bottom line show the effective 7r-electron density for 

 hyperconjugatiou at the saturated atoms. 



