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...