Ab initio study of the one- and two-photon circular dichroism of R-(+)-3-methyl-cyclopentanone

Abstract

One- and two-photon circular dichroism spectra of R-(+)-3-methyl-cyclopentanone, a system that has been the subject of recent experimental studies of (2+1) resonance-enhanced multiphoton ionization circular dichroism, have been calculated with an origin-invariant density functional theory approximation in the region of the lowest electronic excited states, both for the gas phase and for a selection of solvents. A polarizable continuum model is used in the calculations performed on the solvated system. Two low-lying conformers are analyzed, and a comparison of the intensities and characteristic features is made with the corresponding two-photon absorption for each species, also for the Boltzmann-averaged spectra. The effect of the choice of geometry, basis set, and exchange-correlation functional is carefully analyzed. It is found that a density functional theory approach using the Coulomb attenuating method variant of Becke's three-parameter exchange and the Lee-Yang-Parr correlation functionals with correlation-consistent basis sets of double-zeta quality can reproduce the experimental electronic circular dichroism spectra very well. The features appearing in experiment are characterized in terms of molecular excitations, and the differences in the response of each state in the one- and two-photon processes are highlighted.

Circular Dichroism in Ion Yields of Femtosecond‐Laser Mass Spectrometry

“…The quest for stereo-selective synthesis has stimulated considerable interest in attempts to either separate or transform enantiomers by means of laser excitation employing different kinds of circular polarization. [6,7] Furthermore, CD effects are not limited to the linear regime, as measurements of two-and multiphoton CD effects have been the topic of experimental [8] and theoretical [9,10] reports as well. Recently, CD measurements have been combined with laser mass spectrometry utilizing multi-photon ionization.…”

“…[16] In addition, the electronic energy levels of 3-MCP are well characterized [17,18] and have been extensively investigated-experimentally and theoretically-with regard to linear and nonlinear circular dichroism. [10][11][12][13] …”

Two‐photon absorption circular‐linear dichroism on axial enantiomers

“…culations carried out using DALTON 37 with the aug-ccpVDZ basis set, which was proven to perform adequately in one and two-photon absorption and circular dichroism studies in different organic compounds. [27][28][29][30]26,38 For 2-Naphtol we employed the geometry of one of the two naphthyl moieties of the (geometry optimized) structure of RBN, without further re-optimization, and carried out the calculation of the TPA cross section for the lowest twenty excited electronic states using again the aug-cc-pVDZ basis set.…”

Note: Derivation of two-photon circular dichroism—Addendum to “Two-photon circular dichroism” [J. Chem. Phys. 62, 1006 (1975)]

“…Ignoring all terms higher than linear in ζ, we can write the product of the two expressions in Eqs. (6) and (7) according to…”

“…4 Both the first experimental realization of TPCD and the origin independent computational treatment led to a large amount of applications which take place in the interplay between theory and experiment. [5][6][7][8] Therefore, the study of Tinoco in 1975 remains fundamental for the theoretical treatment of this molecular property.…”