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Volumn 312, Issue 5780, 2006, Pages 1637-1640

The role of πσ* excited states in the photodissociation of heteroaromatic molecules

Author keywords

[No Author keywords available]

Indexed keywords

HYDROGEN; HYDROGEN BONDS; KINETIC ENERGY; MOLECULAR DYNAMICS; NITROGEN COMPOUNDS; PHOTODISSOCIATION; PHOTOLYSIS;

EID: 33745158285     PISSN: 00368075     EISSN: 10959203     Source Type: Journal    
DOI: 10.1126/science.1125436     Document Type: Article
Times cited : (348)

References (29)
  • 3
    • 33745123019 scopus 로고    scopus 로고
    • note
    • Imidazole, pyrrole, and phenol were obtained commercially (Aldrich, Gillingham, UK, 98%). Pyrrole, at its room temperature vapor pressure (∼11 torr) and diluted in 700 torr of Ar, was introduced into the photolysis region in the form of a pulsed, skimmed molecular beam. For imidazole and phenol, solid samples were packed in the tube leading to the same pulsed molecular beam source and heated to ∼100°C (imidazole) or 60°C (phenol), and the resulting vapor entrained in 700 torr of Ar before expansion into the interaction region.
  • 6
    • 33745171491 scopus 로고    scopus 로고
    • note
    • R = 67.07 dalton, 66.08 dalton, and 93.11 dalton), d = 0.368 m is the length of the flight path, and t is the measured H atom TOF.
  • 7
    • 33745135831 scopus 로고    scopus 로고
    • note
    • 2 - 1)/2 is the second-order Legendre polynomial, β takes limiting values of +2 in the case of prompt dissociation after excitation via a parallel transition (i.e., μ lies along the breaking bond) and -1 in the case of a perpendicular transition. Less anisotropic fragment recoil distributions (i.e., with β closer to 0) are observed in the case of predissociations (i.e., where the excited state lifetime is comparable to, or longer than, the rotational period of the parent molecule).
  • 9
    • 33745122681 scopus 로고    scopus 로고
    • note
    • Equilibrium structures and vibrational frequencies discussed in this work were calculated using Gaussian 03 (Revision B.04, M. J. Frisch et al., Gaussian, Inc., Pittsburgh, PA, 2003), B3LYP, with a 6-311G(d,p) basis set.
  • 10
    • 33745121912 scopus 로고    scopus 로고
    • note
    • Convention identifies the N atom involved in the N-H bond in imidazole as atom 1, and the other heavy atoms in the ring labeled by counting in a clockwise direction in the case of the structure depicted in Fig. 1, i.e., C2, N3, etc.
  • 12
    • 33745125772 scopus 로고    scopus 로고
    • note
    • Vibronic coupling is an example of a breakdown of the Born-Oppenheimer separation, which applies when the vibrational and electronic degrees are coupled sufficiently strongly that they cannot be factored. In the case of an electric dipole forbidden transition, inclusion of a quantum of a nonsymmetric vibration changes the overall (vibronic) symmetry and permits the transition (with an intensity that depends on the degree of mixing of the vibrational and electronic wave functions).
  • 28
    • 33745177014 scopus 로고    scopus 로고
    • note
    • 33.
  • 29
    • 33745169739 scopus 로고    scopus 로고
    • note
    • We are grateful to the Engineering and Physical Sciences Research Council UK for financial support via the Portfolio Partnership LASER and to K. N. Rosser for his outstanding practical support of this work.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.