Control of Local Ionization and Charge Transfer in the Bifunctional Molecule 2-Phenylethyl-N,N-dimethylamine Using Rydberg Fingerprint Spectroscopy

Abstract

Local photoionization pathways and charge-transfer dynamics of 2-phenylethyl-N,N-dimethylamine (PENNA) are explored using the recently developed Rydberg fingerprint spectroscopy. PENNA, a molecule that derives its biological significance from its relation to neurotransmitters, has two ionization centers that are separated by an ethyl group. We ionize the molecule in various multiphoton ionization processes using different laser wavelengths. The Rydberg fingerprint spectrum reveals the local nature of the ionization process and identifies the center of charge. We discovered that the laser wavelength provides substantial control over the activation of the individual ionization centers. The resonant (2+1) ionization with 400-nm radiation is dominated by the ejection of an electron from the amine moiety. In contrast, the resonant (1+1) ionization with 266-nm radiation leads predominantly to an ion with the charge in the phenyl group. The clean separation of the two ionization processes allows the exploration of ultrafast charge-transfer dynamics ensuing from a specific starting state characterized by a charged phenyl moiety. The width of the corresponding spectral features suggests that the charge transfer proceeds on a femtosecond time scale, suggesting a strong coupling between the two lowest-energy electronic surfaces of the PENNA cation.

Ultrafast structural and isomerization dynamics in the Rydberg-exited Quadricyclane: Norbornadiene system

“…[5][6][7][8][9] In our research we demonstrated that Rydberg electrons are remarkably sensitive to the geometrical structure of the underlying molecular core. The sensitivity to the molecular structure arises from the phase shift that the Rydberg electron encounters when passing the molecular ion a) rudakovfm@ornl.gov.…”

Ultrafast Dynamics of 1,3-Cyclohexadiene in Highly Excited States

“…While historically static structure determination methods, such as electron diffraction, have been adapted to fast time scales, there are some limitations, for example, relating to the size of the molecular system [10][11][12][13][14]. Rydberg fingerprint spectroscopy (RFS) takes advantage of the fact that the binding energies of electrons in Rydberg states are sensitive towards the arrangement of atoms in the ion core [15][16][17][18][19]. Because the structure in a Rydberg state most often closely resembles that of the ion state, the spectra of these states feature sharp peaks without vibrational broadening [20][21][22].…”

Spectroscopy and femtosecond dynamics of the ring opening reaction of 1,3-cyclohexadiene

“…Based on a series of studies elucidating the photoionization pathways involving excited valence and Rydberg states, [37][38][39][40][41][42] we employed the two-color three-photon scheme illustrated in Fig. Based on a series of studies elucidating the photoionization pathways involving excited valence and Rydberg states, [37][38][39][40][41][42] we employed the two-color three-photon scheme illustrated in Fig.…”