Matrix Isolation Fourier Transform Infrared and Ab Initio Studies of the 193-nm-Induced Photodecomposition of Formamide

Lundell, Jan; Krajewska, Magdalena; Räsänen, Markku

doi:10.1021/jp9810724

Cited by 87 publications

(152 citation statements)

References 59 publications

Supporting

Mentioning

138

Contrasting

Order By: Relevance

“…In a previous study, the ground state of the neutral molecule was studied employing the larger 6-311ϩϩG(2d,2p) basis set. 12 The results obtained in the present calculations nearly duplicate those results, and are in good agreement with the parameters as determined in experimental studies. The ground state of the radical cation derives in our calculations from the removal of an electron from the 10aЈ orbital, which is generally described as nonbonding and localized on the oxygen atom.…”

Section: A Calculationssupporting

confidence: 90%

“…[7][8][9][10][11][12] These properties and the structural properties of the molecule in its electronic ground state have also been the subject of several theoretical studies. [13][14][15] Although the bond lengths and bonding angles of the ground-state structure of formamide have been well characterized in various microwave, 16 -19 gas-phase electron-diffraction, 20 and vibration-rotational studies, 21 the planarity of the molecule has for quite some time been the subject of debate, 12,22,23 in particular in relation to the possibility of a nonplanar peptide unit and in relation to the amide resonance model.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Excited and ionic states of formamide: An excited-state photoelectron spectroscopy and ab initio study

Steege

Lagrost

Buma

et al. 2002

The Journal of Chemical Physics

View full text Add to dashboard Cite

. (2002). Excited and ionic states of formamide: an excited-state photoelectron spectroscopy and ab initio study. Journal of Chemical Physics, 117, 8270. DOI: 10.1063/1.1513456 General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. High-resolution excited-state photoelectron spectroscopy has been applied to unravel the spectroscopic and dynamic properties of the excited states of formamide populated by two-and three-photon excitation. In combination with ab initio calculations, this approach has led to various reassignments of previously observed states, and to the observation of new states. One of the aspects that particularly emerges from the present study is the important role of vibronic coupling, which leads to states of heavily mixed character. Projection on the ionic manifold-as is done in our studies-is, however, able to determine the various contributions of the wave function. Our studies have enabled us as well to resolve an apparent disagreement concerning the values of the ionization energies of the ground and first excited state of the radical cation. We find here adiabatic values of 10.233Ϯ0.008 and 10.725Ϯ0.020 eV, respectively. A final issue our studies shed light on concerns the vibrational properties of the ground state of the radical cation.

show abstract

Section: A Calculationssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Excited and ionic states of formamide: An excited-state photoelectron spectroscopy and ab initio study

Steege

Lagrost

Buma

et al. 2002

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…− , should be the result of a reaction between H atoms and successively NH (induced from reaction 2) and NH 2 radicals (Lundell et al 1998). The HCOṙ adical formation observed during the VUV irradiation process (band at 1850 cm −1 ) (Fig.…”

Section: Ocnmentioning

confidence: 96%

Tentative identification of urea and formamide in ISO-SWS infrared spectra of interstellar ices

Raunier

Chiavassa

Duvernay

et al. 2004

A&A

127

146

View full text Add to dashboard Cite

Abstract. Laboratory experiments involving vacuum ultraviolet (VUV) irradiation of solid isocyanic acid (HNCO) at 10 K, followed by infrared spectroscopy (FTIR), are used to interpret the complex spectra associated with Interstellar Medium (ISM) dust grains, particularly the spectra associated with the icy phase observed toward dense molecular clouds. The comparison of the infrared spectra of the photolysis products with spectra recorded from the protostellar source NGC 7538 IRS9 shows that the "unexplained" 1700 cm −1 feature can be attributed to the contribution of several species H 2 CO (formaldehyde), HCONH 2 (formamide) and H 2 NCONH 2 (urea) mixed with H 2 O as the main contributor. Urea, formaldehyde and NH− (ammonium cyanate) may also contribute to a band at 1470 cm −1 , widely observed in many protostellar infrared sources and which remains up to now poorly explained in numerous ISO-SWS spectra. Isocyanic acid could be a precursor of formamide and urea in interstellar ices.

show abstract

“…Furthermore, there was also the question of the photochemical stability of the amide moiety under the present experimental conditions. Lundell et al [37] reported the first photolysis experiments of formamide in both argon and xenon matrices through irradiation with an excimer laser operating at 193 nm (ArF), and observed two major channels, leading to the formation of CO and HNCO, complexed with NH 3 and H 2 , respectively. The vacuum UV photolysis (k > 160 nm) of acetamide was also studied at low temperature (in argon matrix) by Duvernay et al [38], which found HNCO:CH 4 and CO:CH 3 NH 2 molecular complexes as main products, together with acetimidic acid.…”

Section: Photochemical Experimentsmentioning

confidence: 99%

In situ direct photoproduction of ketenes from substituted coumarins isolated in solid argon: The case of N-(2-oxo-2H-chromen-3-yl)acetamide

Kuş

Breda

Fausto

2009

Journal of Molecular Structure

View full text Add to dashboard Cite

a b s t r a c tIn this study, the infrared spectrum of N-(2-oxo-2H-chromen-3-yl)acetamide (3-acetamidocoumarin; 3AC) isolated in solid argon, at 10 K, was obtained and assigned. In consonance with the relative energies of the three conformers predicted theoretically, only the most stable form was observed experimentally. This conformer is stabilized by two intramolecular hydrogen bonds and is similar to the structural unit of 3AC found in crystalline phase. Upon in situ UV (k > 215 nm) irradiation of the matrix-isolated compound, the characteristic IR intense band due to the antisymmetric stretching vibration of the ketene (AC@C@O) group was observed, indicating occurrence of the ring-opening isomerization reaction to the open-ring ketene isomeric of 3AC. In consonance with the theoretical structural predictions for the most stable isomers of this photoproduct, the experimental data indicates that it is produced in the E arrangement of the (O@)CAC@CAC(@C@O) fragment. There were also experimental indications pointing to occurrence of a second photoreaction channel, corresponding to decarbonylation. On the other hand, contrarily to what is generally observed for a-pyrones derivatives, including unsubstituted coumarin, no photochemical production of Dewar isomer of 3AC was observed. This last result, follows the trend observed for 2-pyrone-3-carboxylate, and seems to be a quite general rule for matrix-isolated a-pyrones bearing relatively volumous substituents at the position 3, as a consequence of the unfavorable relaxation of the matrix around the guest molecule that would be required to accommodate the Dewar isomers of these compounds, whose structure deviates strongly from planarity, thus mismatching the primarily occupied matrix sites.

show abstract

Matrix Isolation Fourier Transform Infrared and Ab Initio Studies of the 193-nm-Induced Photodecomposition of Formamide

Cited by 87 publications

References 59 publications

Excited and ionic states of formamide: An excited-state photoelectron spectroscopy and ab initio study

Excited and ionic states of formamide: An excited-state photoelectron spectroscopy and ab initio study

Tentative identification of urea and formamide in ISO-SWS infrared spectra of interstellar ices

In situ direct photoproduction of ketenes from substituted coumarins isolated in solid argon: The case of N-(2-oxo-2H-chromen-3-yl)acetamide

Contact Info

Product

Resources

About