Structures, Aromaticity and Raman Spectroscopy of Double Hanging Ring Molecules [(GnHn-1~m)(GnHn–1~m)](G = C, Si, Ge;n = 3, 5, 6, 7, 8;m = +1, –1, 0, +1, +2)

Theoretical calculations of Double Hanging Ring Molecule(DHRM) [(GnHn-1~m)(GnHn–1~m)](G = C, Si, Ge; n = 3, 5, 6, 7, 8; m=+1, –1, 0, +1, +2) were performed via Gaussian 09 with the method of Density Functional Theory(DFT). Geometrical optimization, Potential Energy surface Scan(PES), Degree of Aromaticity(DOA) and Nucleus Independent Chemical Shift(NICS) were computed to study the optimal structures and aromaticity of DHRMs. Ring Stretching Vibration Raman Spectroscopy(RSVRSF) was predicted to seek the relation between RSVRSF and aromaticity of DHRMs. The results show optimal structures of DHRMs[(GnHn-1~m)(GnHn–1~m)](n = 3, 5～8); DA = 90° is the stable structure when n = 3, 7, 8; while n = 5 corresponds to DA = 30°, n = 6 corresponds to DA = 50°; the correlation between DOA and NICS of DHRMs is quadratic; the value of RSVRSF of DHRM approximates to its corresponding single ring molecule, which could act as characteristic frequency of ring molecule to identify its aromaticity; the correlation between RSVRSF and DOA is quadratic, and that between RSVRSF and NICS is linear.