The complete structure of furan

Bak, Børge; Christensen, Daniel; Dixon, William B.; Hansen‐Nygaard, Lise; Andersen, John Rastrup; Schottländer, Marianne

doi:10.1016/0022-2852(62)90219-9

Cited by 228 publications

(61 citation statements)

References 8 publications

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“…The analysis of the CASPT2 results clearly shows that the presence of a single additional orbital of the a u symmetry in the active space is one of the key factors responsible for the correct reproduction of the energy gap between the two 1 1 B u transition, which is reduced by over 40 % becoming similar to experiment. Another important aspect of including single additional orbital of the a u symmetry in the conventional 0550 active space is the dramatic reduction (26-50 %) of the off-diagonal CASPT2 coupling between the 1 B u states, which again brings the corresponding multi-state CASPT2 energy splitting much closer to the experimental value.…”

Section: Discussionmentioning

confidence: 60%

“…An analysis of the 1 1 B u and 2 1 B u CASSCF wave functions suggests close similarity between both states. The major configuration (43%) in the 1 1 B u wave function originates from the HOMO ? LUMO excitation; there are also sizable additions of the HOMO -2?LUMO (20%) and HOMO ?…”

Section: Introductionmentioning

confidence: 99%

“…Spectroscopy of 5-membered heterocyclic rings has been extensively studied for several decades [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Excited states of thiophene attracted particular attention as this molecule constitutes the smallest building block of oligo and polythiophenes-materials extensively used in organic electronics [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

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The elusive excited states of bithiophene: a CASPT2 detective story

Andrzejak

Witek

2011

Theor Chem Acc

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Section: Discussionmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The elusive excited states of bithiophene: a CASPT2 detective story

Andrzejak

Witek

2011

Theor Chem Acc

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“…C 2v symmetry. Comparision of the AM1 data for the pyrrole, furan, and thiophene molecules with those for microwave absorption [45][46][47] indicates that the calculation in general reproduces correctly the experimental geometry. However, the calculated CC, CN, and CO bond lengths are again lengthened by 1.01-1.02 times whereas the CS bond length is shortened by the same amount.…”

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confidence: 75%

Calculations of derivatives of porphin and porphyrazine with an annulated five-membered heteroaromatic ring using a modified INDO method

2008

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Quantum-chemical calculations for series of porphin (H 2 P) and porphyrazine (H 2 PA) derivatives whose molecules contain a 3,4-annulated five-membered heteroaromatic ring of pyrrole, furan, and thiophene as well as 1,2,5-triazole, 1,2,5-oxadiazole, and 1,2,5-thiadiazole have been carried out by the AM1 and INDO/Sm methods (m means "modified parametrization"). As follows from the unrestricted Hartree-Fock AM1 calculations, the ground state energy of the a isomer is lower than that of the b isomers for all compounds, the a and b isomers being NH isomers with the additional five-membered ring fused to a pyrrolenine or pyrrole ring, respectively. Condensation of the five-membered ring for the b isomers of the H 2 P derivatives is shown to extend the main conjugation path from 18-membered to 21-membered cyclopolyene. However, the 18-membered cyclopolyene for the a isomers of the H 2 P derivatives and 16-membered cyclopolyene for both isomers of the H 2 PA derivatives prove to be isolated from the five-membered ring carrying six π-electrons. Based on INDO/Sm computations of electronic absorption spectra of the H 2 P and H 2 PA derivatives, it is shown that the Q x level of the a isomers is sensitive to the nature of the annulated ring whereas the Q y level is practically not shifted. On the contrary, the Q x level of the b isomers is relatively insensitive to the nature of the annulated ring while the Q y level decreases monotonously in the H 2 P and H 2 PA series, being the first excited state level for the majority of the derivatives (X is along the NH-HN axis; Y, perpendicular to it). The electronic absorption spectra at the border of the visible and near-UV regions are determined mainly by two high-intensity G

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“…These minimum energy structures resolve the ambiguity of the experimental PhD investigation regarding the structure, and are clearly consistent with the key findings of these experiments. Table 1 Comparison of the interatomic bond lengths, d, and bond angles, θ, of gas-phase furan obtained from experimental results by Bak et al [15] and by Liecheski and Rankin [16] with the results of the GGA-RPBE calculations performed here, and of two earlier DFT calculations. The naming convention for the atoms in the furan ring used here are shown in Fig.…”

Section: General Discussion and Conclusionmentioning

confidence: 99%

The structure and bonding of furan on Pd(111)

2010

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The structure and bonding of molecular furan, C 4 H 4 O, on Pd(111) has been investigated using density functional theory (DFT) calculations and the results compared with those of a recent experimental investigation using scanned-energy mode photoelectron diffraction (PhD). The DFT results confirm the orientation of the molecular plane to be essentially parallel to the surface and show a clear energetic preference for one of the two possible structures identified in the PhD study, namely that with the molecule centred over the hollow sites of the surface. Two slightly different geometries at the hollow sites are found to be essentially energetically equivalent; in both cases, one Pd surface atom bonds to two C atoms, while two other Pd atoms each bond to one C atom. These structures differ in that in one case the pair of C atoms bonding to a single Pd atom are both β-C (C atoms not bonded to O in the furan molecule), whereas in the second case this pair of C atoms comprises one β-C and one α-C (adjacent to the O atom in furan). In both structures the C-Pd bonding is accompanied by displacements of the H and O atoms away from the surface and out of the molecular plane and local C-Pd coordination consistent with a rehybridisation of the C bonding to sp 3 character.

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The complete structure of furan

Cited by 228 publications

References 8 publications

The elusive excited states of bithiophene: a CASPT2 detective story

The elusive excited states of bithiophene: a CASPT2 detective story

Calculations of derivatives of porphin and porphyrazine with an annulated five-membered heteroaromatic ring using a modified INDO method

The structure and bonding of furan on Pd(111)

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