Photoelectron spectroscopy of terpenoids and prediction of their rate constants in atmospheric oxidation reactions

Abstract

The electronic structures of six mono-terpenoids and two of their oxygenated derivatives were studied by He I photoelectron spectroscopy (PES). The observed bands were interpreted on the basis of empirical arguments and theoretical calculations. The first vertical ionization potentials for β -pinene, α-terpinene, terpinolene, γ -terpinene, limonene, myrcene, citral, and terpinene-4-ol were determined to be 8. 73, 7.57, 8.26, 8.30, 8.53, 8.68, 8.71, and 8.77 eV, respectively. Most of these values have not been determined by PES before. The correlations of the first vertical ionization potentials of these compounds to the natural logarithms of rate constants for their reactions with the radicals OH, NO 3 , and O 3 were determined. The correlation coefficients for their reactions with OH, NO 3 , and O 3 were 0.97, 0.91, and 0.95, respectively. This method is a powerful technique for predicting the rate constants for the atmospheric oxidation reactions of terpenoids. photoelectron spectroscopy, ionization potential, outer-valence Green's function (OVGF), rate constant Citation:Wang X P, Tong S R, Ge M F, et al. Photoelectron spectroscopy of terpenoids and prediction of their rate constants in atmospheric oxidation reactions.

Electronic Circular Dichroism of Chiral Alkenes: B3LYP and CAM‐B3LYP Calculations

“…As for trans ‐cyclooctene, α ‐pinene, and β ‐pinene, we computed excitation energies that arrive to 8.5 eV; at this point, we believe it to be important to carry out a deeper analysis as to whether this phenomenon affects our results. For these compounds, the experimental vertical IEs of 8.72, 8.38, and 8.73 eV are about 2.2 eV larger than the corresponding ones predicted in this work by B3LYP functional (−ε HOMO = 6.43, 6.21, and 6.54 eV, respectively), whereas, the CAM‐B3LYP functional predicts the IEs at 7.94, 7.70, and 8.04 eV, respectively. Similar findings were described by Lehtonen et al studying the electronic excitation spectra of trans ‐1,3‐butadiene and trans ‐2‐propeniminium with various functionals.…”

Letter: Determination of Ionization Energies of a Monoterpene Series by Atmospheric Pressure Photoionization Using Tunable Vacuum Ultraviolet Synchrotron Radiation

“…Finally, the sum of the two ion-signal intensities was calculated, leading to a better statistic, and compared it to the literature (Figure 2). 7,11,13,14,22 Our experimental IE value is in very good agreement with tabulated ones, validating our experimental approach. It must be noted that Fang et al 12 obtained a significant lower value, i.e.…”

“…The experimental set-up was first tested with limonene, for which photoelectron spectra 7,11,14 or photoionization efficiency curves 12,13 have already been published. Below 8.4 eV, only low signal-to-noise ratios were recorded.…”

“…[4][5][6] A correlation between the ionization energies (IEs) of monoterpenes and their reactivity has been proposed. 7 Although photoionization of pinene [7][8][9][10] and limonene 7,[11][12][13][14] has been largely examined, the amount and quality of data for other monoterpenes remain low. Even if photoelectron photoion coincidence 15 spectroscopy can be considered as a gold standard, it requires large sample consumption (several milligrams).…”

Angle‐Resolved Strong‐Field Ionization of Polyatomic Molecules: More than the Orbitals Matters

“…A similar argument holds for a-terpinene, for which the photoelectron spectrum shows a gap of about 3 eV between the first and second peaks. [32] This can be interpreted in terms of the D 0 -D 1 energy difference. While a photoelectron spectrum is not available for a-phellandrene, it is reasonable to expect that the D 0 -D 1 gap is similar (i.e.…”