Characterization of singlet ground and low-lying electronic excited states of phosphaethyne and isophosphaethyne

Ingels, Justin B.; Turney, Justin M.; Richardson, Nancy A.; Yamaguchi, Yukio; Schaefer, Henry F.

doi:10.1063/1.2222356

Cited by 13 publications

(20 citation statements)

References 60 publications

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“…Thus, the self-interaction error is likely to be small in these calculations. Calculations with the equation-of-motion coupled cluster method yield T o = 4.31 eV for PCH(1 1 A″), in perfect agreement with the observed value …”

Section: Resultssupporting

confidence: 81%

Computational Tests of Quantum Chemical Models for Excited and Ionized States of Molecules with Phosphorus and Sulfur Atoms

2014

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Time-dependent density functional theory (TD-DFT) and electron propagator theory (EPT) are used to calculate the electronic transition energies and ionization energies, respectively, of species containing phosphorus or sulfur. The accuracy of TD-DFT and EPT, in conjunction with various basis sets, is assessed with data from gas-phase spectroscopy. TD-DFT is tested using 11 prominent exchange-correlation functionals on a set of 37 vertical and 19 adiabatic transitions. For vertical transitions, TD-CAM-B3LYP calculations performed with the MG3S basis set are lowest in overall error, having a mean absolute deviation from experiment of 0.22 eV, or 0.23 eV over valence transitions and 0.21 eV over Rydberg transitions. Using a larger basis set, aug-pc3, improves accuracy over the valence transitions via hybrid functionals, but improved accuracy over the Rydberg transitions is only obtained via the BMK functional. For adiabatic transitions, all hybrid functionals paired with the MG3S basis set perform well, and B98 is best, with a mean absolute deviation from experiment of 0.09 eV. The testing of EPT used the Outer Valence Green's Function (OVGF) approximation and the Partial Third Order (P3) approximation on 37 vertical first ionization energies. It is found that OVGF outperforms P3 when basis sets of at least triple-ζ quality in the polarization functions are used. The largest basis set used in this study, aug-pc3, obtained the best mean absolute error from both methods -0.08 eV for OVGF and 0.18 eV for P3. The OVGF/6-31+G(2df,p) level of theory is particularly cost-effective, yielding a mean absolute error of 0.11 eV.

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Section: Resultssupporting

confidence: 81%

Computational Tests of Quantum Chemical Models for Excited and Ionized States of Molecules with Phosphorus and Sulfur Atoms

2014

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“…An important group of publications are devoted to various spectroscopic studies including electronic, vibrational–rotational, Raman, microwave and lower-energy regions, , SEP (stimulated emission pumping), and NMR . Theoretical studies range from Hartree–Fock calculations to multireference CI, MP4SDQ, CASSCF, RMP2, CISD, and CCSD(T) . We have reported studies of protonation and hydrogen bond formation involving HCP. , …”

Section: Introductionmentioning

confidence: 99%

FCl:PCX Complexes: Old and New Types of Halogen Bonds

et al. 2012

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MP2/aug'-cc-pVTZ calculations have been performed to investigate the halogen-bonded complexes FCl:PCX, for X = NC, CN, F, H, CCH, CCF, CH(3), Li, and Na. Although stable complexes with a F-Cl···P halogen bond exist that form through the lone pair at P (configuration I), except for FCl:PCCN, the more stable complexes are those in which FCl interacts with the C≡P triple bond through a perturbed π system (configuration II). In complexes I, the nature of the halogen bond changes from traditional to chlorine-shared and the interaction energies increase, as the electron-donating ability of X increases. The anionic complex FCl:PC(-) has a chlorine-transferred halogen bond. SAPT analyses indicate that configuration I complexes with traditional halogen bonds are stabilized primarily by the dispersion interaction. The electrostatic interaction is the most important for configuration I complexes with chlorine-shared halogen bonds and for configuration II complexes except for FCl:PCNa for which the induction term is most important. The F-Cl stretching frequency is red-shifted upon complexation. EOM-CCSD/(qzp,qz2p) spin-spin coupling constants have been obtained for all FCl:PCX complexes with configuration I. (1)J(F-Cl) decreases upon complexation. (2X)J(F-P) values are quadratically dependent upon the F-P distance and are very sensitive to halogen-bond type. (1X)J(Cl-P) tends to increase as the Cl-P distance decreases but then decreases dramatically in the chlorine-transferred complex FCl:PC(-) as the Cl-P interaction approaches that of a covalent Cl-P bond. Values of (1)J(F-Cl) for configuration II are reduced relative to configuration I, reflecting the longer F-Cl distances in II compared to those of the neutral complexes of I. Although the F-P and Cl-P distances in configuration II complexes are shorter than these distances in the corresponding configuration I complexes, (2X)J(F-P) and (1X)J(Cl-P) values are significantly reduced, indicating that coupling through the perturbed C-P π bond is less efficient. The nature of F-P coupling for configuration II is also significantly different, as evidenced by the relative importance of PSO, FC, and SD components.

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“…Although EOM‐CCSD was shown to yield very accurate vertical excitation energies 36, 43, its single‐reference character makes it less suitable at strongly distorted geometries. Thus, the aforementioned EOM‐CCSD results will serve as benchmarks for the calibration of CASSCF and MRCI calculations which should be more applicable in such cases.…”

Section: Resultsmentioning

confidence: 99%

Ab initio study of the photochemistry of aminopyrimidine

Zechmann

Barbatti

2008

Int J of Quantum Chemistry

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Complete active space self-consistent field (CASSCF), multi-reference configuration interaction calculations (MR-CISD), and equation of motion coupledcluster with singles and doubles (EOM-CCSD) calculations are presented in order to elucidate the photodeactivation pathways of 6-aminopyrimidine after vertical excitation to the S 1 1 n* state. Vertical excitation energies are reported up to the S 7 state. Two S 1 excited state minima, both of 1 n* character, and three strongly puckered 1 * minima on the crossing seam (MXS) between the S 0 and the S 1 potential energy surface were found. Nonadiabatic reaction paths are discussed by linearly interpolating between the two minima and all MXS, which explain and extend observations made in recent surface-hopping dynamics CASSCF investigations Lischka, J Phys Chem A 2007, 111, 2852].State-averaged complete active space self-consistent field (SA-CASSCF) and multireference configuration interaction calculations with single and double excitations (MR-CISD) calculations were carried out for the optimization of stationary points and conical intersections, calculation of excitation energies, and search for reaction paths. In the FIGURE 1. Structure and labeling of 6AP.

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Characterization of singlet ground and low-lying electronic excited states of phosphaethyne and isophosphaethyne

Cited by 13 publications

References 60 publications

Computational Tests of Quantum Chemical Models for Excited and Ionized States of Molecules with Phosphorus and Sulfur Atoms

Computational Tests of Quantum Chemical Models for Excited and Ionized States of Molecules with Phosphorus and Sulfur Atoms

FCl:PCX Complexes: Old and New Types of Halogen Bonds

Ab initio study of the photochemistry of aminopyrimidine

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