Department of Physics;
Liaoning University;
Shenyang 10036;
China;
College of Mathematics and Information Engineering;
Chongqing University of Education;
Chongqing 400065;
China;
School of Science;
Chongqing University of Technology;
Chongqing 400050;
China;
density functional theory(DFT)and time-dependent DFT(TDDFT); excited-state proton transfer; intramolecular hydrogen bonding; π-conjugation-substitution;