The lower rydberg states of formaldehyde

Lessard, C. R.; Moule, D. C.; Bell, Stephen

doi:10.1016/0009-2614(74)85101-8

Cited by 13 publications

(8 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[2][3][4][5][6] warrant additional discussion. In order to clarify their natures, the spatial distributions of the final-state resonance orbitals in each case can be unambiguously established by examining the pseudospectral functions contained in the appropriate excitation-energy interval.…”

Section: B Photoionization Resonancesmentioning

confidence: 99%

“…[2][3][4][5][6] and Tables II-IV are combined to form total vertical electronic photoabsorption cross sections corresponding to the three independent electric -field polarization directions in the molecular frame, associated with 1 A 1 -tB 1 (x, out of plane), 1 A 1 -1 B 2 (y, in plane), and 1 A 1 -1 A 1 (z, in plane) electronic transitions. Although there is no direct appropriate experimental data relating to these, the polarization cross sections can be compared with the previously reported CI S-T calculations.…”

Section: Polarization Cross Sectionsmentioning

confidence: 99%

“…In the present report, it is sufficient to infer and describe the natures of the final-state resonance orbitals qualitatively, making use only of the photoionization cross sections of Figs. [2][3][4][5][6] and an understanding of the virtual orbitals anticipated on basis of valence calculations. 24 • 47 • 51 • 52 In Fig.…”

Section: B Photoionization Resonancesmentioning

confidence: 99%

See 2 more Smart Citations

Photoabsorption in formaldehyde: Intensities and assignments in the discrete and continuous spectral intervals

Langhoff

Orel

Rescigno

et al. 1978

The Journal of Chemical Physics

View full text Add to dashboard Cite

Theoretical investigations of total and partial-channel photoabsorption cross sections in molecular formaldehyde are reported employing the Stieltjes-Tchebycheff (s-T) technique and separated-channel static-exchange (!YO) calculations. Vertical one-electron dipole spectra for the 2b 2 (n), lb 1(7T), 5a 1(a), I b 2 , and 4a 1 canonical molecular orbitals are obtained using Hartree-Fock frozen-core functions and large basis sets of compact and diffuse normalizable Gaussians to describe the photoexcited and ejected electrons. The calculated discrete excitation spectra provide reliable zeroth-order approximations to both valence and Rydberg transitions, and, in particular, the 2b 2 (n)-msa 1 , npa 1 , npb 2 , and nda 2 IVO spectra are in excellent accord with recent experimental assignments and available intensity measurements. Convergent (S-T) photoionization cross sections in the static-exchange (IVO) approximation are obtained for the 15 individual partial channels associated with ionization of the five occupied molecular orbitals considered. Resonance features in many of the individual-channel photoionization cross sections are attributed to contributions frorn valencelike a 1 a*(CO), a 1 a*(CH), and b 2 a*(CH)/7Ty *(CO) molecular orbitals that appear in the photoionization continua, rather than in the corresponding one-electron discrete spectral intervals. The vertical electronic cross sections for 1 A 1 -+ 1 B 1 , 1 B 2 , and 1 A 1 excitations are in generally good accord with previously reported CI (s-T) predictions of continuum orbital assignments and intensities, although some discrepancies due to basis-set differences are present in the 1 B 1 and 1 B 2 components, and larger discrepancies apparently due to channel coupling are present in the 1 A 1 -+ 1 A 1 cross section. Partialchannel vertical electronic cross sections for the production of the five lowest parent-ion electronic states are found to be in general agreement with the results of very recent synchrotron-radiation photoelectron branching-ratio measurements in the 20 to 30 eV excitation energy interval. Most important in this connection is the tentative verification of the predicted orderings in intensities of the partial-channel cross sections, providing support for the presence of a strong ka 1

show abstract

Section: B Photoionization Resonancesmentioning

confidence: 99%

Section: Polarization Cross Sectionsmentioning

confidence: 99%

Section: B Photoionization Resonancesmentioning

confidence: 99%

See 1 more Smart Citation

Photoabsorption in formaldehyde: Intensities and assignments in the discrete and continuous spectral intervals

Langhoff

Orel

Rescigno

et al. 1978

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…1, where they are compared with the scheme used in the current work. Most of these studies have made use of resonances with the (n,3p) Rydberg states, which lie 7.9-8.4 eV above the ground state and were first observed in VUV absorption [15][16][17] and inelastic electron scattering experiments. 18 (In this state label, ''n'' denotes the non-bonding 2b 2 orbital from which an electron is removed and ''3p'' denotes the Rydberg-like orbital into which the electron is excited.…”

Section: Introductionmentioning

confidence: 99%

A 1 + 1′ resonance-enhanced multiphoton ionization scheme for rotationally state-selective detection of formaldehyde via the Ã ¹A₂ ← X̃ ¹A₁ transition

Park

Krüger

Meyer

et al. 2016

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

The formaldehyde molecule is an important model system for understanding dynamical processes in small polyatomic molecules. However, prior to this work, there have been no reports of a resonance-enhanced multiphoton ionization (REMPI) detection scheme for formaldehyde suitable for rovibrationally state-selective detection in molecular beam scattering experiments. Previously reported tunable REMPI schemes are either non-rotationally resolved, involve multiple resonant steps, or involve many-photon ionization steps. In the current work, we present a new 1 + 1' REMPI scheme for formaldehyde. The first photon is tunable and provides rotational resolution via the vibronically allowed Ã (1)A2 ← X[combining tilde] (1)A1 transition. Molecules are then directly ionized from the Ã state by one photon of 157 nm. The results indicate that the ionization cross section from the 4(1) vibrational level of the Ã state is independent of the rotational level used as intermediate, to within experimental uncertainty. The 1 + 1' REMPI intensities are therefore directly proportional to the Ã ← X[combining tilde] absorption intensities and can be used for quantitative measurement of X[combining tilde]-state population distributions.

show abstract

“…In addition to finding excellent state selection routes, the results shed some new light on the 3p Rydberg states of this well-studied molecule. The literature concerning the spectroscopy of H 2 CO is sizable, including studies of emission, 14 absorption, [14][15][16][17][18][19][20][21][22][23][24][25] electric dichroism spectroscopy, 26 electron-impact spectroscopy, 27,28 multiphoton ionization, [29][30][31] photoelectron spectroscopy, [32][33][34][35] ZEKE-PFI, 36 and photoionization spectroscopy. 19,37,38 These studies have revealed much concerning the geometries, transition energies, and rovibronic energy levels for the ground and excited states for both neutral and ionic formaldehyde.…”

Section: Introductionmentioning

confidence: 99%

Multiphoton ionization and photoelectron spectroscopy of formaldehyde via its 3p Rydberg states

Kim

Anderson

2001

The Journal of Chemical Physics

View full text Add to dashboard Cite

The resonance-enhanced multiphoton ionization ͑REMPI͒ spectrum of formaldehyde, two photon resonant in the region of the 1 A 2 (3p x), 1 A 1 (3p y), and 1 B 2 (3p z) states, is reported. The 1 A 2 (3p x) state spectrum is dominated by the 3 Ј ͑CH 2 scissors͒, 4 Ј ͑CH 2 out-of-plane bending͒, 5 Ј ͑CH 2 asymmetric stretching͒, and 6 Ј ͑CH 2 rock͒ modes, with weaker bands observed for excitation of the 2 Ј ͑CO stretching͒ mode. Vibrational analysis of the spectrum provides many new frequencies for the 1 A 2 (3p x) state, not resolved or accessible in single photon spectroscopic measurements. Photoelectron spectroscopy is used to probe the nature of the vibronic levels associated with the 1 A 2 (3p x) intermediate state, to measure vibrational frequencies of the resulting cations, and to identify useful routes for preparing vibrational state-selected H 2 CO ϩ. It is found that H 2 CO͓ 1 A 2 (3p x)͔ is a well-behaved Rydberg state, generating cations in the same vibrational level that was populated in the intermediate. Cations with mode-selective excitation of up to 0.62 eV can be produced. Ab initio calculations are used to help assign the cation vibrations. In contrast to the well-behaved 1 A 2 (3p x) state, the 1 A 1 (3p y) and 1 B 2 (3p z) states are strongly mixed with each other and with valence states.

show abstract

The lower rydberg states of formaldehyde

Cited by 13 publications

References 13 publications

Photoabsorption in formaldehyde: Intensities and assignments in the discrete and continuous spectral intervals

Photoabsorption in formaldehyde: Intensities and assignments in the discrete and continuous spectral intervals

A 1 + 1′ resonance-enhanced multiphoton ionization scheme for rotationally state-selective detection of formaldehyde via the Ã ¹A₂ ← X̃ ¹A₁ transition

Multiphoton ionization and photoelectron spectroscopy of formaldehyde via its 3p Rydberg states

Contact Info

Product

Resources

About

The lower rydberg states of formaldehyde

Cited by 13 publications

References 13 publications

Photoabsorption in formaldehyde: Intensities and assignments in the discrete and continuous spectral intervals

Photoabsorption in formaldehyde: Intensities and assignments in the discrete and continuous spectral intervals

A 1 + 1′ resonance-enhanced multiphoton ionization scheme for rotationally state-selective detection of formaldehyde via the Ã 1A2 ← X̃ 1A1 transition

Multiphoton ionization and photoelectron spectroscopy of formaldehyde via its 3p Rydberg states

Contact Info

Product

Resources

About

A 1 + 1′ resonance-enhanced multiphoton ionization scheme for rotationally state-selective detection of formaldehyde via the Ã ¹A₂ ← X̃ ¹A₁ transition