The Jahn–Teller and related effects in the cyclopentadienyl radical. I. The ab initio calculation of spectroscopically observable parameters

Ab initio calculations are performed for the X 2E1″ and A 2A2″ states of the cyclopentadienyl radical. An important goal of these calculations is to guide the analysis of the experimentally observed A 2A2″– X 2E1″ electronic spectrum. Vibrational frequencies for both the X and A state are reported. Large changes in frequency between the states for out-of-plane vibrations are found, leading to the expectation that overtones of these modes will appear strongly in the spectrum. Additionally, spectroscopically obtainable parameters describing the Jahn–Teller effect are calculated for the X state. Using all this information the X−A electronic spectrum is predicted for both C5H5 and C5D5.

[1]  B. Applegate,et al.  The Jahn–Teller and related effects in the cyclopentadienyl radical. II. Vibrational analysis of the à 2A2″–X̃ 2E1″ electronic transition , 2001 .

[2]  P. Botschwina,et al.  Theoretical study of the Jahn–Teller effect in X̃ 2E CH3O , 2000 .

[3]  S. Canuto,et al.  Ground state structure of C5H5 and van der Waals interaction with He and Ne , 1999 .

[4]  E. Bernstein,et al.  Solvation of cyclopentadienyl and substituted cyclopentadienyl radicals in small clusters. I. Nonpolar solvents , 1999 .

[5]  E. Bernstein,et al.  Solvation of cyclopentadienyl and substituted cyclopentadienyl radicals in small clusters. II. Cyanocyclopentadienyl with polar solvents , 1999 .

[6]  M. Robb,et al.  A CASSCF study of the cyclopentadienyl radical: conical intersections and the Jahn–Teller effect , 1999 .

[7]  R. Sadygov,et al.  Unusual conical intersections in the Jahn-Teller effect: The electronically excited states of Li3 , 1999 .

[8]  T. Barckholtz,et al.  The Calculation of Spectroscopic Jahn−Teller Parameters by ab Initio Methods , 1999 .

[9]  M. Keil,et al.  Vibrational structures in the A2E′′←X2E′ system of the lithium trimer: high-resolution spectroscopy and ab initio calculations , 1999 .

[10]  W. Demtröder,et al.  Unambiguous Proof for Berry's Phase in the Sodium Trimer: Analysis of the Transition A 2 E ′ ′ ← X 2 E ′ , 1998 .

[11]  T. Barckholtz.  Quantitative insights about molecules exhibiting Jahn-Teller and related effects , 1998 .

[12]  M. Gordon,et al.  Systematic Location of Intersecting Seams of Conical Intersection in Triatomic Molecules: The 1 2A′–2 2A′ Conical Intersections in BH2 , 1998 .

[13]  D. Yarkony,et al.  Conical Intersections: Diabolical and Often Misunderstood , 1998 .

[14]  D. Yarkony,et al.  Energies and derivative couplings in the vicinity of a conical intersection. II. CH2(2 3A″,3 3A″) and H2S(1 1A″,2 1A″), unexpected results in an ostensibly standard case , 1997 .

[15]  F. Bernardi,et al.  Conical Intersection Mechanism for Photochemical Ring Opening in Benzospiropyran Compounds , 1997 .

[16]  B. Kendrick.  Geometric Phase Effects in the Vibrational Spectrum of Na{sub 3}({ital X}) , 1997 .

[17]  D. Yarkony.  Current Issues in Nonadiabatic Chemistry , 1996 .

[18]  A. Ellis,et al.  High Resolution Electronic Spectroscopy of ZnCH3 and CdCH3 , 1993, High Resolution Spectroscopy.

[19]  I. N. Ragazos,et al.  A conical intersection mechanism for the photochemistry of butadiene. A MC-SCF study , 1993 .

[20]  T. Miller,et al.  High resolution laser spectroscopy of asymmetrically deuterated cyclopentadienyl radicals: A study of vibronic degeneracy resolution and Jahn–Teller distortion , 1993 .

[21]  G. Herzberg,et al.  Molecular Spectra and Molecular Structure , 1992 .

[22]  T. Miller,et al.  Rotationally resolved electronic spectrum of jet-cooled deuterated cyclopentadienyl radical , 1989 .

[23]  H. Köppel,et al.  Impact of totally symmetric vibrations on the e⊗e Jahn-Teller effect , 1989 .

[24]  M. Heaven,et al.  Rotationally resolved electronic spectrum of jet-cooled cyclopentadienyl radical , 1988 .

[25]  R. A. Kennedy,et al.  Novel effects in the laser induced fluorescence spectrum of C6F+6 , 1986 .

[26]  L. Pasternack,et al.  Excitation and emission spectra of the 2A″2 ↽ → 2E″1 system of the gas-phase cyclopentadienyl radical , 1983 .

[27]  V. Bondybey,et al.  The Jahn–Teller effect in C6 F+6 , 1981 .

[28]  H. Sakurai,et al.  Chemistry of organosilicon compounds. 131. Substituent effects by deuterium and alkyl groups and carbon-13 hyperfine coupling constants of cyclopentadienyl radicals as studied by electron spin resonance , 1980 .

[29]  V. Bondybey,et al.  Jahn–Teller distortions in C6H3F3+ and C6H3Cl3+ , 1980 .

[30]  R. Meyer,et al.  Jahn-teller effect in cyclopentadienyl radical: delocalized vibronic valence isomerisation , 1979 .

[31]  E. Davidson,et al.  Potential surfaces for the planar cyclopentadienyl radical and cation , 1979 .

[32]  W. C. Lineberger,et al.  Laser photoelectron spectrometry of C5H−5: A determination of the electron affinity and Jahn–Teller coupling in cyclopentadienyl , 1977 .

[33]  R. Engleman,et al.  Electronic absorption spectrum of the cyclopentadienyl radical (C5H5) and its deuterated derivatives , 1970 .

[34]  G. Porter,et al.  The photolytic preparation of cyclopentadienyl and phenyl nitrene from benzene derivatives , 1968, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[35]  R. L. Kuczkowski.  The Microwave Spectrum of Dinitrogen Trioxide , 1965 .

[36]  H. Mcconnell,et al.  Study of Molecular Orbital Degeneracy in C5H5 , 1965 .

[37]  R. E. Moss,et al.  ISOTOPE EFFECTS IN ELECTRON SPIN RESONANCE: THE NEGATIVE ION OF CYCLO- OCTATETRAENE-1-d , 1965 .

[38]  A. D. McLachlan,et al.  Dynamical Jahn‐Teller Effect in Hydrocarbon Radicals , 1960 .

[39]  M. Child.  Dynamical Jahn-Teller effect in molecules possessing one four-fold symmetry axis , 1960 .

[40]  L. C. Snyder.  Jahn‐Teller Distortions in Cyclobutadiene, Cyclopentadienyl Radical, and Benzene Positive and Negative Ions , 1960 .

[41]  A. D. Liehr,et al.  On the Stability of Cyclobutadiene, Cyclopentadienyl Radical, and the Benzene Plus One Ion: A Comparison of the Molecular Orbital and Valence Bond Predictions , 1956 .