Document Type: Original Article


1 Department of Chemistry, Saveh Branch, Islamic azad University, Saveh, Iran

2 Department of Chemistry, Bourojerd Branch, Islamic Azad University, Bourojerd, Iran


In the present study, theoretical chemical reactivates Photo isomerization in Cis-Retinal as a Natural Photo switch in Vision. DFT hybrid functional, B3LYP and, post-HF method, were the theoretical methods applied utilizing G09 software. 6-31G+ (d,p) basis set employed for structural optimizations, and single point computations performed using B3LYP/6-31G+(d,p). The isomers cis molecule retinal from 0 to 180 ° in steps of 10 degrees to the trans isomers convert and we calculate the energy in each step, we determined that the most appropriate angle for the conversion of isomers of cis to trans angleq =  90.11 ° the energy barrier less be.It identified that transmission S0® S1 is the most likely transmission


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