Resonant two-photon ionization and ab initio conformational analysis of haloethyl benzenes (PhCH2CH2X,X=Cl,F)

Martin, Danielle E.; Robertson, Evan G.; Morrison, Richard J. S.; Dobney, Bruce
October 2007
Journal of Chemical Physics;10/7/2007, Vol. 127 Issue 13, p134307
Academic Journal
The S1←S0 transitions of the gaseous (2-fluoroethyl)-benzene (FEB) and (2-chloroethyl)-benzene (CEB) have been investigated using a combination of two-color resonant two-photon ionization and UV-UV hole burning spectroscopy. Both anti and gauche conformers have been identified on the basis of rotational band contour analysis supported by ab initio calculations on the ground and electronically excited states. The gauche origin band of FEB at 37 673 cm-1 is redshifted 50 cm-1 relative to the corresponding anti origin, while CEB origin bands overlap at 37 646 cm-1. Relative conformational stability and populations in the jet have been estimated for both molecules, based on the intensity ratio of S1←S0 band origin transitions. These are compared with a range of related molecules with the structural motif PhCH2CH2X (X=CH3,CH2CH3,NH2,OH,COOH,CCH,CN). Theory and experimental results for FEB and CEB show repulsive interactions between the halogen substituents and the π cloud of the phenyl rings destabilizing the gauche conformers, but the preference for the anti conformers is relatively modest. The gauche conformer origins show very different hybrid character: FEB is largely b type, while CEB is an a/c hybrid in keeping with theoretically computed TM “rotations” (θelec) of -7° and -56°, respectively. This difference is attributed largely to rotation of the side chain in opposite directions about the C1Cα bond. Spectra of FEB(H2O) and CEB(H2O) single water clusters show evidence of an anti conformation in the host molecule.


Related Articles

  • A spectroscopic investigation of the nonrigid–rigid transition of (benzene)13 during free jet expansion. Easter, David C.; Baronavski, A. P.; Hawley, Michael // Journal of Chemical Physics;10/1/1993, Vol. 99 Issue 7, p4942 

    We have traced the evolution of the benzene-h6 transition in (C6H6)(C6D6)12 as a function of time (distance from the nozzle) in a supersonic expansion. Taking advantage of the special properties of the isotopically substituted (benzene)13 resonant two-photon ionization spectrum, we present the...

  • Photo- and charged-particle-ionization of He and D[sub 2] studied with COLTRIMS. Abdallah, M. A.; Achler, Matthias; Braeuning, H.; Braeuning-Deminian, Angela; Cocke, C. L.; Czasch, Achim; Doerner, R.; Landers, A.; Mergel, V.; Osipov, T.; Prior, M.; Schmidt-Boecking, H.; Singh, M.; Weber, T.; Wolff, W.; Wolf, H. E. // AIP Conference Proceedings;2000, Vol. 506 Issue 1, p101 

    The COLTRIMS (COLd Target Recoil Ion Momentum Spectroscopy) approach to final-state momentum imaging is now being widely used in at least a dozen accelerator and synchrotron-radiation laboratories in the world and its use is growing rapidly. The technique combines fast imaging detectors with a...

  • The 2 1Ag state of isolated cis,trans-1,3,5,7-octatetraene: Two-color resonance enhanced two-photon ionization studies. Buma, Wybren Jan; Kohler, Bryan E.; Shaler, Thomas A. // Journal of Chemical Physics;1/1/1992, Vol. 96 Issue 1, p399 

    Vibrationally resolved 1 1Ag→2 1Ag excitation spectra and decay times for cis,trans-1,3,5,7-octatetraene seeded in a supersonic He expansion have been measured by two-color resonance enhanced two-photon ionization spectroscopy. The excitation energy of the 1 1Ag→2 1Ag 0–0...

  • Polarization resolved two-photon resonant ionization spectroscopy of indole and 3-methylindole. Cable, J. R. // Journal of Chemical Physics;2/1/1990, Vol. 92 Issue 3, p1627 

    Two-photon resonant, four-photon ionization spectra of vapor phase indole and 3-methylindole have been taken using both linearly and circularly polarized excitation. From these measurements, the wavelength dependent polarization ratio Ω has been determined. The value of Ω has been used to...

  • Resonant two-photon ionization study of jet-cooled amino acid: L-phenylalanine and its monohydrated complex. Lee, Kang Taek; Sung, Jiha; Lee, Kwang Jun; Kim, Seong Keun; Park, Young Dong // Journal of Chemical Physics;5/15/2002, Vol. 116 Issue 19, p8251 

    L-phenylalanine (Phe), one of the aromatic amino acids, and its hydrated clusters were generated in supersonic expansion and investigated by resonant two-photon ionization. Excitation spectra of Phe and Phe-(H[sub 2]O)[sub 1] were obtained near their S[sub 0]-S[sub 1] origins. We found that, by...

  • Structural transitions in benzene–argon clusters: Size and temperature effects. Schmidt, Martin; Le Calvé, Jacques; Mons, Michel // Journal of Chemical Physics;4/15/1993, Vol. 98 Issue 8, p6102 

    The resonant two-photon ionization spectra of the first benzene–Arn (n≤8) clusters are interpreted in the light of a model calculation, including local energy minima determinations and Monte Carlo simulations. Based on spectral shift information, two types of structures are...

  • Two-photon ionization studies of binary aromatic van der Waals clusters: Benzene...chlorobenzene and (chlorobenzene)2. Lu, Wenyun; Hu, Yihua; Lin, Zhenyang; Yang, Shihe // Journal of Chemical Physics;6/8/1996, Vol. 104 Issue 22, p8843 

    Jet-cooled van der Waals dimers of benzene (B) and chlorobenzene (BCl) were studied by one-color resonant two-photon ionization through the S0→S1 transition of the chlorobenzene. The spectra of BCl...B and (BCl)2 in the 0–0 band both show two main features with different spectral...

  • Fast decay of high vibronic S[sub 1] states in gas-phase benzene. Clara, M.; Hellerer, Th.; Neusser, H.J. // Applied Physics B: Lasers & Optics;2000, Vol. 71 Issue 3, p431 

    Abstract. Lifetimes of different vibronic levels at high excess energies in the S[sub 1 state of isolated benzene molecules are measured using for the first time a two-photon ionization pump-probe technique with UV femtosecond pulses. For the 6[sup 1] 1[sup 3] state (3290 cm[sup -1] excess...

  • Stability of two-component alkali clusters formed on helium nanodroplets. Droppelmann, G.; Mudrich, M.; Schulz, C. P.; Stienkemeier, F. // European Physical Journal D -- Atoms, Molecules, Clusters & Opti;Nov2009, Vol. 52 Issue 1-3, p67 

    The stability of two-component clusters consisting of light (Na or K) and heavy (Rb or Cs) alkali atoms formed on helium nanodroplets is studied by femtosecond laser ionization in combination with mass spectrometry. Characteristic stability patterns reflecting electron shell-closures are...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics