Resonantly enhanced multiphoton ionization and zero kinetic energy photoelectron spectroscopy of benzo[e]pyrene

Harthcock, Colin; Zhang, Jie; Kong, Wei

doi:10.1016/j.cplett.2012.11.036

Cited by 10 publications

(14 citation statements)

References 41 publications

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“…The value of the scaling factor is within the typical range for calculations using the B3LYP functional. [31][32][33][34][35][36][37] A feature of Gaussian 09 is inclusion of Herzberg-Teller coupling for simulations of vibronic transitions, often with very reasonable accuracy for intensity distributions. 45 The resulting spectrum can further assist with the assignment of the observed REMPI transitions.…”

Section: Experimental Setup and Calculation Methodsmentioning

confidence: 99%

“…However, a problem with Gaussian 09, regardless of methods of calculation, is the uncertainty in the energy of closely spaced excited electronic states. [31][32][33][34][35][36][37] Consequently in Figure 2, we show the simulated spectra with Herzberg-Teller coupling for both the S 1 ← S 0 and the S 2 ← S 0 transitions of triphenylene. Although the lack of an origin band could potentially complicate the assignment of the spectrum, fortunately in this case, the agreement between simulation and experiment in Figure 2 is quite reasonable.…”

Section: Experimental Setup and Calculation Methodsmentioning

confidence: 99%

“…30 In recent years, we have undertaken the mission of mapping out the low frequency vibrational modes of PAHs using ZEKE spectroscopy. [31][32][33][34][35][36][37] So far we have reported four pericondensed species including pyrene, benzo[a]pyrene (BaP), benzo[e]pyrene (BeP), and benzo[g,h,i]perylene (BghiP) as well as three cata-condensed species including tetracene, pentacene, and chrysene. [31][32][33][34][35][36][37] Our results together with previous matrix isolation spectroscopy (MIS) [38][39][40][41] and other experimental efforts offer the possibility of a comprehensive analysis of the vibrational modes of a few selected cationic species, thereby benchmarking theoretical calculations and astrophysical modeling.…”

Section: Introductionmentioning

confidence: 99%

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Zero kinetic energy photoelectron spectroscopy of triphenylene

Harthcock

Zhang

Kong

2014

The Journal of Chemical Physics

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We report vibrational information of both the first electronically excited state and the ground cationic state of jet-cooled triphenylene via the techniques of resonantly enhanced multiphoton ionization (REMPI) and zero kinetic energy (ZEKE) photoelectron spectroscopy. The first excited electronic state S1 of the neutral molecule is of A1' symmetry and is therefore electric dipole forbidden in the D3h group. Consequently, there are no observable Franck-Condon allowed totally symmetric a1' vibrational bands in the REMPI spectrum. All observed vibrational transitions are due to Herzberg-Teller vibronic coupling to the E' third electronically excited state S3. The assignment of all vibrational bands as e' symmetry is based on comparisons with calculations using the time dependent density functional theory and spectroscopic simulations. When an electron is eliminated, the molecular frame undergoes Jahn-Teller distortion, lowering the point group to C2v and resulting in two nearly degenerate electronic states of A2 and B1 symmetry. Here we follow a crude treatment by assuming that all e' vibrational modes resolve into b2 and a1 modes in the C2v molecular frame. Some observed ZEKE transitions are tentatively assigned, and the adiabatic ionization threshold is determined to be 63 365 ± 7 cm(-1). The observed ZEKE spectra contain a consistent pattern, with a cluster of transitions centered near the same vibrational level of the cation as that of the intermediate state, roughly consistent with the propensity rule. However, complete assignment of the detailed vibrational structure due to Jahn-Teller coupling requires much more extensive calculations, which will be performed in the future.

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Section: Experimental Setup and Calculation Methodsmentioning

confidence: 99%

Section: Experimental Setup and Calculation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Zero kinetic energy photoelectron spectroscopy of triphenylene

Harthcock

Zhang

Kong

2014

The Journal of Chemical Physics

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“…[28][29][30][31][32][33] The system is differentially pumped with a time-of-flight (TOF) mass spectrometer inside the detector chamber. The detection chamber is located inside the source chamber and is separated from the source chamber via a 2 mm diameter homemade skimmer and three extending arms.…”

Section: Experimental and Computational Proceduresmentioning

confidence: 99%

Electronic spectra and excited-state dynamics of acridine and its hydrated clusters

Harthcock

Zhang

Kong

et al. 2017

The Journal of Chemical Physics

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We combine results from several different experiments to investigate the photophysics of acridine (Ac) and its hydrated clusters in the gas phase. Our findings are also compared with results from condensed phase studies. Similar to measurements of Ac dissolved in hydrocarbons, the lifetime of the first electronically excited state of isolated Ac in vacuum is too short for typical resonantly enhanced multiphoton ionization (REMPI) and laser induced fluorescence (LIF) experiments, hence no signal from REMPI and LIF can be attributed to monomeric Ac. Instead, sensitized phosphorescence emission spectroscopy is more successful in revealing the electronic states of Ac. Upon clustering with water, on the other hand, the lifetimes of the excited states are substantially increased to the nanosecond scale, and with two water molecules attached to Ac, the lifetime of the hydrated cluster is essentially the same as that of Ac in aqueous solutions. Detailed REMPI and ultraviolet-ultraviolet hole-burning experiments are then performed to reveal the structural information of the hydrated clusters. Although the formation of hydrogen bonds results in energy level reversal and energy separation between the first two excited states of Ac, its effect on the internal geometry of Ac is minimal, and all clusters with 1-3 water molecules demonstrate consistent intramolecular vibrational modes. Theoretical calculations reveal just one stable structure for each cluster under supersonic molecular beam conditions. Furthermore, different from mono- and di-water clusters, tri-water clusters consist of a linear chain of three water molecules attached to Ac. Consequently, the fragmentation pattern in the REMPI spectrum of tri-water clusters seems to be dominated by water trimer elimination, since the REMPI spectrum of Ac·W is largely reproduced in the Ac mass channel, but not in the Ac·W or Ac·W channel.

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“…In recent years, the technique of resonance enhanced multiphoton ionization spectroscopy (REMPIS) [1,2] has become an important means for the study of photo-ionization, dissociation dynamics of molecules and atoms due to its simple equipment and high detection sensitivity. It can not only provide information about the energy level structure, but also associate with the dynamic process of some chemical reaction [3,4].…”

Section: Introductionmentioning

confidence: 99%