REMPI spectroscopy and theoretical calculations of cis and trans 3-fluoro-N-methylaniline

Vibrational Spectra and Theoretical Calculations of cis- and trans-3-Fluoro-N-methylaniline in the Neutral (S0) and Cationic (D0) Ground States

“…The REMPI spectra of jet-cooled 3FNMA rotamers have been well studied in a previous report . As shown in Figure a, the band origins of the S 1 ← S 0 electronic transition are determined to be 33 816 and 34 023 cm –1 for cis - and trans -3FNMA, respectively.…”

“…As for the NHCH 3 inversion mode, I 2 , the frequencies are found to be 580 and 564 cm –1 for cis - and trans -3FNMA + , respectively. The red shift of 16 cm –1 for the trans rotamer with respect to the cis one may arise from the similar reason as that in the S 1 state . That is, because of the electron delocalization in the conjugation system, some kind of long-range interaction “through bond” seems to occur between the CH 3 group and the fluorine atom in 3FNMA.…”

“…Its conformation analysis in the S 0 state has been performed by microwave spectroscopy, indicating the existence of two rotamers with near-planar equilibrium configuration, which are denoted by cis - and trans -3FNMA, depending on the orientation of the meta -fluorine atom with respect to the amino hydrogen atom. Recently, we have investigated the molecular properties of 3FNMA rotamers in the S 1 state and electronic transition energies by using the resonance-enhanced multiphoton ionization (REMPI) spectroscopy and theoretical calculations . It is found that the most stable rotamer of 3FNMA is the cis one for S 0 state but the trans one for D 0 state.…”

Influence of Doppler effect on the absorption in the process of resonance multiphoton ionization

“…21  denotes the coherence relaxation rate and R is the ionization one. The electromagnetic field with frequency  pumps the transition of |1>↔|2> whose frequency is 21 Taking Doppler effect into account, the transition frequency between two energy levels 5 perceived by laser photon should be )…”

“…Especially it can be used for the observation of the energy level which can't be realized through the single photon process. Many experimental and theoretical researches about this domain have been conducted, and a series of achievements have been obtained [5][6][7][8]. The most obvious result is that there is an intermediate resonance absorption state during REMPI process.…”