Abstract: Using density functional B3P86 method, we optimized the ground state stable geometries of the gasphase acetone molecules and charged ions at the level of 6311++G(d,p). At the same time, using the method of timedependent density functional theory (TDDFT), we studied the low excited state properties of the gasphase acetone molecules and ions. The results show that the energy of the system increases gradually, the difference between S1 excited state energy and ground state energy decreases, molecular fluorescence wavelength increases sharply, and the number of electron transition orbitals decreases with the increase of the number of electrons obtained by molecules.

Key words: acetone molecule, ion； low excited state； orbital transition