The absorption and single vibronic level fluorescence spectra of 2-aminopyridine

Hollas, J. Michael; Musa, Hamdan; Ridley, Trevor

doi:10.1016/0022-2852(84)90247-9

Cited by 17 publications

(12 citation statements)

References 16 publications

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“…The wavelength of the excitation laser is determined during each experiment using a wavemeter ͑Burleigh͒ and the resulting transition energies are found to agree well with the literature values. [27][28][29]53,54,58 The electronically excited molecules are ionized by a 200 nm laser pulse that is derived from the second synchronously pumped dye laser. Details about the frequency tripling scheme used to obtain this short wavelength are described elsewhere.…”

Section: Methodsmentioning

confidence: 99%

“…51,52 This angle decreases to zero when the molecule is excited to the S 1 singlet state at 298.8 nm. 53,54 In an earlier experiment, 55 we observed the one-color two-photon ionization photoelectron spectra of 2-aminopyridine via several S 1 vibronic levels, and analyzed the vibrational structure of the cation in its ground state. The nonradiative relaxation of 2-aminopyridine out of its S 1 singlet state is not yet understood clearly, even though it has been the subject of several investigations.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Time-delayed two-color photoelectron spectra of aniline, 2-aminopyridine, and 3-aminopyridine: Snapshots of the nonadiabatic curve crossings

Kim

Schick

Weber

1995

The Journal of Chemical Physics

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Articles you may be interested inTwo-color pump-probe laser spectroscopy instrument with picosecond time-resolved electronic delay and extended scan range Rev. Sci. Instrum. 76, 114301 (2005); 10.1063/1.2126808 Vibrational spectra of aniline-Ar n van der Waals cations (n=1 and 2) observed by twocolor ''threshold photoelectron'' [zero kinetic energy (ZEKE)photoelectron] spectroscopy J. Chem. Phys. 96, 6399 (1992); 10.1063/1.462634 Twocolor threshold photoionization of jetcooled aniline: Vibrationally selective autoionization J. Chem. Phys. 84, 6771 (1986); 10.1063/1.450680 Autoionizing Rydberg structure observed in the vibrationally selective, twocolor, threshold photoionization spectrum of jetcooled aniline J. Chem. Phys. 83, 4820 (1985); 10.1063/1.449010Timeresolved twocolor photoacoustic and multiphoton ionization spectroscopy of aniline

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Time-delayed two-color photoelectron spectra of aniline, 2-aminopyridine, and 3-aminopyridine: Snapshots of the nonadiabatic curve crossings

Kim

Schick

Weber

1995

The Journal of Chemical Physics

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“…[12,13] The mass selective 2C-R2PI spectra of (2PY) 2 and (2AP) 2 around their respective electronic origins are shown in Fig. 4a,b. The (2PY) 2 dimer is C 2h symmetric in both electronic states, and only the S 0 →S 2 To calculate the quenching factor Γ= exp (-Σ i S i ), we employed the Huang-Rhys factors S i from experimental fluorescence spectra of the 2PY and 2AP monomers, [13,15] which gave Γ exp = 0.025 for (2AP) 2 and 0.035 for (2PY) 2 . The vibronic coupling to intramolecular vibrational modes is seen to quench the Davydov splittings by factors of 40 and 30, respectively!…”

Section: Spectroscopic Determination Of Excitonic Splittings: (2-pyrimentioning

confidence: 99%

Excitonic Splittings in Jet–Cooled Molecular Dimers

Ottiger¹,

Leutwyler²

2011

Chimia

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In more than 60 years of research on molecular excitons, there has been extensive theoretical work but few experimental investigations have rigorously tested the predictions of exciton coupling theories. In centrosymmetric doubly H-bonded molecular dimers with identical chromophores, the S0-->S1 electronic transition dipole moments of the monomers combine in a parallel and antiparallel fashion, giving the S0-S1 and S0-->S2 transitions of the dimer. One of these is strictly symmetry-forbidden and the other fully allowed. Minimal perturbations such as 12C/13C or H/D isotopic substitution lift the symmetry restrictions sufficiently to render both transitions allowed. The excitonic (Davydov) splitting can then be measured as the energy difference between the respective vibrationless O0(0) bands. We have measured the mass-specific vibronic spectra of the centrosymmetric H-bonded dimers (2-pyridone)2 and (2-aminopyridine)2 that are supersonically cooled to a few K and isolated in molecular beams, using two-color resonant two-photon ionization spectroscopy. Comparison of the all-12C- and 13C- isotopomer spectra yield excitonic splittings of delta(exp) = 43.5 and 10.5 cm(-1), respectively. The corresponding splittings calculated by high-level ab initio methods (RI-CC2/aug-cc-pVTZ) are 20 to 50 times larger. These purely electronic ab initio exciton splittings need to be reduced ('quenched') by vibronic coupling to the optically active vibrational modes. Only after quenching are the experimentally observed exciton splittings correctly reproduced.

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“…The electronic states of 2AP have been well studied by many researchers (17)(18)(19)(20) because of the interest in the coupling between the * and n* states. In addition, 2AP is thought to be a simple model molecule of nucleobase, namely cytosine (21)(22)(23)(24).…”

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Relaxation dynamics of NH stretching vibrations of 2-aminopyridine and its dimer in a supersonic beam

Yamada

Mikami

Ebata

2008

Proc. Natl. Acad. Sci. U.S.A.

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Picosecond time-resolved IR-UV pump-probe spectroscopy has been carried out to elucidate vibrational energy relaxation (VER) of the NH stretching vibrations of 2-aminopyridine monomer (2AP) and dimer [(2AP) 2] in supersonic beams. In bare 2AP, intramolecular vibrational energy redistribution (IVR) of the NH vibrations is described by the two-bath mode model, in which the initial vibrational energy flows to the doorway states rapidly (6.5 ps) and then dissipates into the dense bath states with a time constant of Ϸ20 ps. No clear difference was observed in the IVR lifetime between the symmetric and asymmetric NH 2 stretch modes. In (2AP)2, IVR and vibrational predissociation (VP) were involved in VER. It was found that the rate constants of both IVR and VP of the hydrogen-bonded NH stretching vibration are larger than those of the free NH.hydrogen bond ͉ IVR ͉ vibrational predissociation ͉ time-resolved spectroscopy V ibrational energy relaxation (VER) plays a crucial role in the reactions of chemical, biological, and physical systems, because the reactions initiated by the excitation of a quantum state or a specific site are accompanied by VER (1, 2). Thus, VER has been well studied for several decades in condensed phase (3-7), as well as in the gas phase (7-12). In condensed phase, molecules excited to a specific vibrational level redistribute the vibrational energy very rapidly within the molecules. This process is called intramolecular vibrational energy redistribution (IVR). After IVR, the molecules experience vibrational energy transfer into the solvent molecules and intermolecular modes (6). In the gas phase, VER processes have been studied at the microscopic level by using bare molecules and clusters cooled in molecular beams (13-16). For electronic excited molecules and clusters, a variety of laser spectroscopic works have been carried out for the study of VER, such as the measurements of fluorescence spectra (11, 13) and time profiles of pump-probe methods (14). For the molecules in the electronic ground state, studies on VER have been performed mostly in frequency domain (2,8,15), and the time-domain studies have not been carried out so much until very recently. In 2001, we first reported a study on IVR of the OH stretching vibration of jet-cooled phenol by picosecond IR-UV pump-probe spectroscopy (16). Since then, we have been studying VER of X-H (X ϭ O, N, C) stretching vibrations of aromatic molecules and their clusters. In this study, we report on VER of 2-aminopyridine (2AP) and its dimer [(2AP) 2 ] in supersonic beams.The electronic states of 2AP have been well studied by many researchers (17-20) because of the interest in the coupling between the * and n* states. In addition, 2AP is thought to be a simple model molecule of nucleobase, namely cytosine (21-24). Recently, Schultz and coworkers (21) measured the lifetime of the S 1 (*) state of 2AP clusters and found that the lifetime of (2AP) 2 is remarkably short. They proposed that the formation of the dimer pair accelerates internal conversion of...

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The absorption and single vibronic level fluorescence spectra of 2-aminopyridine

Cited by 17 publications

References 16 publications

Time-delayed two-color photoelectron spectra of aniline, 2-aminopyridine, and 3-aminopyridine: Snapshots of the nonadiabatic curve crossings

Time-delayed two-color photoelectron spectra of aniline, 2-aminopyridine, and 3-aminopyridine: Snapshots of the nonadiabatic curve crossings

Excitonic Splittings in Jet–Cooled Molecular Dimers

Relaxation dynamics of NH stretching vibrations of 2-aminopyridine and its dimer in a supersonic beam

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