The formaldehyde cation: Rovibrational energy level structure and Coriolis interaction near the adiabatic ionization threshold

Schulenburg, A. M.; Meisinger, M.; Radi, P. P.; Merkt, F.

doi:10.1016/j.jms.2008.04.005

Cited by 18 publications

(10 citation statements)

References 36 publications

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“…Recently, we have reported and analyzed a strong a-type Coriolis interaction between the 4 1 and 6 1 vibrational levels of the X ˜+ electronic ground state of the formaldehyde cation. 23 Given that the rovibrational structure of Rydberg states closely resemble that of the cationic state to which the Rydberg series converge, the existence of a similar interaction in the 3p x level of H 2 CO and in the ground state of H 2 CO + is not surprising.…”

Section: Methodsmentioning

confidence: 98%

“…The term value of the 3p x 1 A 2 state determined in the fit (T 0 = 67 728.939(82) cm À1 ) is in good agreement with that determined earlier by Liu et al, 21 and the rigid-rotor rotational constants B and C lie close to the values determined for the cationic ground state. 23 The decrease of the A rigidrotor constant suggests that the HCH angle increases upon ionization. Our analysis supports the conclusion drawn by Liu et al 21 that the observed band is not, as suggested earlier by Mentall et al, 22 a doublet band resulting from an inversion manifold caused by a nonplanar geometry.…”

Section: Methodsmentioning

confidence: 99%

“…The assignment of these two vibrations in the 3p x 1 A 2 state and in the cationic ground state has been difficult to establish unambiguously [19][20][21][22] and some uncertainty concerning the planarity/nonplanarity of the cation in its electronic ground state and the neutral molecule in the 3p Rydberg states persisted until recently. 23 In the X ˜1A 1 and A ˜1A 2 electronic states, n 4 has a lower fundamental frequency than n 6 , whereas the opposite holds true in the cation and the Rydberg manifold. 13,21,23 Liu et al 21 assigned two bands in the photoelectron spectrum of H 2 CO to the n 4 and the n 6 modes of the X ˜+2 B 2 ground state of the cation on the basis of the results of ab initio calculations 14 and determined the corresponding fundamental wave numbers to be 979 cm À1 and 812 cm À1 , respectively.…”

Section: Introductionmentioning

confidence: 99%

“…23 In the X ˜1A 1 and A ˜1A 2 electronic states, n 4 has a lower fundamental frequency than n 6 , whereas the opposite holds true in the cation and the Rydberg manifold. 13,21,23 Liu et al 21 assigned two bands in the photoelectron spectrum of H 2 CO to the n 4 and the n 6 modes of the X ˜+2 B 2 ground state of the cation on the basis of the results of ab initio calculations 14 and determined the corresponding fundamental wave numbers to be 979 cm À1 and 812 cm À1 , respectively. They concluded that the bands observed in the (2+1) REMPI spectra of H 2 CO at 68 542 cm À1 and 68 709 cm À1 correspond to transitions to the 3p x 1 A 2 6 1 and 4 1 levels, respectively, from the fact that the vibrational energy level structure of Rydberg states is similar to that of the cationic state to which the Rydberg series converges.…”

Section: Introductionmentioning

confidence: 99%

“…They concluded that the bands observed in the (2+1) REMPI spectra of H 2 CO at 68 542 cm À1 and 68 709 cm À1 correspond to transitions to the 3p x 1 A 2 6 1 and 4 1 levels, respectively, from the fact that the vibrational energy level structure of Rydberg states is similar to that of the cationic state to which the Rydberg series converges. In a rotationally resolved study of the X ˜+2 B 2 ground state of H 2 CO + by PFI-ZEKE photoelectron spectroscopy, Schulenburg et al 23 then recognized that the 4 1 and 6 1 levels of the cation are subject to a Coriolis interaction.…”

Section: Introductionmentioning

confidence: 99%

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Rotationally resolved spectroscopy and dynamics of the 3px 1A2 Rydberg state of formaldehyde

Meisinger

Schulenburg

Merkt

et al. 2010

Phys. Chem. Chem. Phys.

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The rotational structure of the lowest three vibrational levels (0(0), 6(1) and 4(1)) of the 3p(x) (1)A(2) Rydberg state of formaldehyde has been studied by doubly-resonant three-photon ionization spectroscopy. A strong a-type Coriolis interaction between the in-plane rocking (ν(6)) and out-of-plane bending (ν(4)) modes results in the observation of vibronically forbidden transitions to the 6(1) level from the intermediate Ã(1)A(2) (2(1) 4(3)) level. The full widths at half maximum of the rovibronic transitions to the 4(1) state are considerably larger than to the vibrational ground state and the 6(1) level. The band origin (T(0) = 67 728.939(82) cm(-1)), the rigid rotor rotational constants (A = 9.006(19) cm(-1), B = 1.331(20) cm(-1), and C = 1.135(22) cm(-1)), the Coriolis coupling constant (ξ = 8.86(89) cm(-1)) and the deperturbed fundamental wave numbers of both vibrational modes (v[combining tilde](6) = 808.88(25) cm(-1) and v[combining tilde](4) = 984.92(26) cm(-1)) have been determined for the 3p(x) (1)A(2) Rydberg state. Polarization effects originating from the double-resonance technique have been exploited to detect the Coriolis interaction and investigate how it affects the predissociation dynamics.

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Section: Methodsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Rotationally resolved spectroscopy and dynamics of the 3px 1A2 Rydberg state of formaldehyde

Meisinger

Schulenburg

Merkt

et al. 2010

Phys. Chem. Chem. Phys.

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Pyrolysis Pathways of the Furanic Ether 2-Methoxyfuran

et al. 2015

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Substituted furans, including furanic ethers, derived from nonedible biomass have been proposed as second-generation biofuels. In order to use these molecules as fuels, it is important to understand how they break apart thermally. In this work, a series of experiments were conducted to study the unimolecular and low-pressure bimolecular decomposition mechanisms of the smallest furanic ether, 2-methoxyfuran. Electronic structure (CBS-QB3) calculations indicate this substituted furan has an unusually weak O-CH3 bond, approximately 190 kJ mol(-1) (45 kcal mol(-1)); thus, the primary decomposition pathway is through bond scission resulting in CH3 and 2-furanyloxy (O-C4H3O) radicals. Final products from the ring opening of the furanyloxy radical include 2 CO, HC≡CH, and H. The decomposition of methoxyfuran is studied over a range of concentrations (0.0025-0.1%) in helium or argon in a heated silicon carbide (SiC) microtubular flow reactor (0.66-1 mm i.d., 2.5-3.5 cm long) with reactor wall temperatures from 300 to 1300 K. Inlet pressures to the reactor are 150-1500 Torr, and the gas mixture emerges as a skimmed molecular beam at a pressure of approximately 10 μTorr. Products formed at early pyrolysis times (100 μs) are detected by 118.2 nm (10.487 eV) photoionization mass spectrometry (PIMS), tunable synchrotron VUV PIMS, and matrix infrared absorption spectroscopy. Secondary products resulting from H or CH3 addition to the parent and reaction with 2-furanyloxy were also observed and include CH2═CH-CHO, CH3-CH═CH-CHO, CH3-CO-CH═CH2, and furanones; under the conditions in the reactor, we estimate these reactions contribute to at most 1-3% of total methoxyfuran decomposition. This work also includes observation and characterization of an allylic lactone radical, 2-furanyloxy (O-C4H3O), with the assignment of several intense vibrational bands in an Ar matrix, an estimate of the ionization threshold, and photoionization efficiency. A pressure-dependent kinetic mechanism is also developed to model the decomposition behavior of methoxyfuran and provide pathways for the minor bimolecular reaction channels that are observed experimentally.

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Pyrolysis of the Simplest Carbohydrate, Glycolaldehyde (CHO−CH₂OH), and Glyoxal in a Heated Microreactor

Porterfield¹,

Baraban²,

Troy

et al. 2016

J. Phys. Chem. A

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Both glycolaldehyde and glyoxal were pyrolyzed in a set of flash-pyrolysis microreactors. The pyrolysis products resulting from CHO-CH2OH and HCO-CHO were detected and identified by vacuum ultraviolet (VUV) photoionization mass spectrometry. Complementary product identification was provided by argon matrix infrared absorption spectroscopy. Pyrolysis pressures in the microreactor were about 100 Torr, and contact times with the microreactors were roughly 100 μs. At 1200 K, the products of glycolaldehyde pyrolysis are H atoms, CO, CH2═O, CH2═C═O, and HCO-CHO. Thermal decomposition of HCO-CHO was studied with pulsed 118.2 nm photoionization mass spectrometry and matrix infrared absorption. Under these conditions, glyoxal undergoes pyrolysis to H atoms and CO. Tunable VUV photoionization mass spectrometry provides a lower bound for the ionization energy (IE)(CHO-CH2OH) ≥ 9.95 ± 0.05 eV. The gas-phase heat of formation of glycolaldehyde was established by a sequence of calorimetric experiments. The experimental result is ΔfH298(CHO-CH2OH) = -75.8 ± 1.3 kcal mol(-1). Fully ab initio, coupled cluster calculations predict ΔfH0(CHO-CH2OH) of -73.1 ± 0.5 kcal mol(-1) and ΔfH298(CHO-CH2OH) of -76.1 ± 0.5 kcal mol(-1). The coupled-cluster singles doubles and noniterative triples correction calculations also lead to a revision of the geometry of CHO-CH2OH. We find that the O-H bond length differs substantially from earlier experimental estimates, due to unusual zero-point contributions to the moments of inertia.

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The formaldehyde cation: Rovibrational energy level structure and Coriolis interaction near the adiabatic ionization threshold

Cited by 18 publications

References 36 publications

Rotationally resolved spectroscopy and dynamics of the 3px 1A2 Rydberg state of formaldehyde

Rotationally resolved spectroscopy and dynamics of the 3px 1A2 Rydberg state of formaldehyde

Pyrolysis Pathways of the Furanic Ether 2-Methoxyfuran

Pyrolysis of the Simplest Carbohydrate, Glycolaldehyde (CHO−CH₂OH), and Glyoxal in a Heated Microreactor

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The formaldehyde cation: Rovibrational energy level structure and Coriolis interaction near the adiabatic ionization threshold

Cited by 18 publications

References 36 publications

Rotationally resolved spectroscopy and dynamics of the 3px 1A2 Rydberg state of formaldehyde

Rotationally resolved spectroscopy and dynamics of the 3px 1A2 Rydberg state of formaldehyde

Pyrolysis Pathways of the Furanic Ether 2-Methoxyfuran

Pyrolysis of the Simplest Carbohydrate, Glycolaldehyde (CHO−CH2OH), and Glyoxal in a Heated Microreactor

Contact Info

Product

Resources

About

Pyrolysis of the Simplest Carbohydrate, Glycolaldehyde (CHO−CH₂OH), and Glyoxal in a Heated Microreactor