The storage of the solar energy by the isomerization of molecular is a new developing direction. The dynamic NMR (DNMR) is a effective means to study the reaction of isomerization. With the help of the interprization of

1

H NMR spectra

it can be recognized that in a p-aminoazobenzene molecular the four hydrogen atoms of the benzene with a amino constitute a typical AA'XX' spin system

which has four coupling constants. And the product of the photo-isomerization reaction exhibits another (AA'XX')

*

spin system.

According to the integral ratio of the (AA'XX')

*

system to the (AA'XX') system

we measured the ratio of the the p

roduct to the reactant under the different UV irradiation time at 2537×10

-10

m and knew the whole dynamic course.

From

1

H NMR and

13

C NMR spectra

the influence of photo-isomerization reaction on the chemical shifts of every group or atom of the molecular can be understood.