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Jin J, Zhang Q, Bornhauser P, Knopp G, Marquardt R, Radi PP. Rovibrational investigation of a new high-lying 0 u + state of Cu 2 by using two-color resonant four-wave-mixing spectroscopy. J Chem Phys 2022; 156:184305. [PMID: 35568551 DOI: 10.1063/5.0087743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A highly excited electronic state of dicopper is observed and characterized for the first time. The [39.6]0u +-X1Σg +(0g +) system is measured at rotational resolution by using degenerate and two-color resonant four-wave-mixing, as well as laser induced fluorescence spectroscopy. Double-resonance experiments are performed by labeling selected rotational levels of the ground state by tuning the probe laser wavelength to transitions in the well-known (1-0) band of the B0u +-X1Σg +(0g +) electronic system. Spectra obtained by scans of the pump laser in the UV wavelength range were then assigned unambiguously by the stringent double-resonance selection rules. The absence of a Q-band suggests a parallel transition (ΔΩ = 0) and determines the term symbol of the state as 0u + in Hund's case (c) notation. The equilibrium constants for 63Cu2 are Te = 39 559.921(92) cm-1, ωe = 277.70(14) cm-1, Be = 0.104 942(66) cm-1, and re = 2.2595(11) Å. These findings are supported by high-level ab initio calculations at the MRCI+Q level, which clearly identifies this state as resulting from a 4p ← 3d transition. In addition, three dark perturber states are found in the v = 1 and v = 2 vibrational levels of the new state. A deperturbation analysis characterizes the interaction and rationalizes the anomalous dips in the excitation spectrum of the [39.6]0u +-X1Σg +(0g +) system.
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Affiliation(s)
- Jiaye Jin
- Photon Science Division, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Qiang Zhang
- Photon Science Division, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Peter Bornhauser
- Photon Science Division, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Gregor Knopp
- Photon Science Division, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Roberto Marquardt
- Laboratoire de Chimie Quantique, Institut de Chimie, Université de Strasbourg, 4 rue Blaise Pascal - CS90032, 67081 Strasbourg Cedex, France
| | - Peter P Radi
- Photon Science Division, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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The dicarbon bonding puzzle viewed with photoelectron imaging. Nat Commun 2019; 10:5199. [PMID: 31729361 PMCID: PMC6858380 DOI: 10.1038/s41467-019-13039-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 10/17/2019] [Indexed: 11/09/2022] Open
Abstract
Bonding in the ground state of C\documentclass[12pt]{minimal}
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\begin{document}$${}_{2}$$\end{document}2 is still a matter of controversy, as reasonable arguments may be made for a dicarbon bond order of \documentclass[12pt]{minimal}
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\begin{document}$$4$$\end{document}4. Here we report on photoelectron spectra of the C\documentclass[12pt]{minimal}
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\begin{document}$${}_{2}^{-}$$\end{document}2− anion, measured at a range of wavelengths using a high-resolution photoelectron imaging spectrometer, which reveal both the ground \documentclass[12pt]{minimal}
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\begin{document}$${X}^{1}{\Sigma}_{\mathrm{g}}^{+}$$\end{document}X1Σg+ and first-excited \documentclass[12pt]{minimal}
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\begin{document}$${a}^{3}{\Pi}_{{\mathrm{u}}}$$\end{document}a3Πu electronic states. These measurements yield electron angular anisotropies that identify the character of two orbitals: the diffuse detachment orbital of the anion and the highest occupied molecular orbital of the neutral. This work indicates that electron detachment occurs from predominantly \documentclass[12pt]{minimal}
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\begin{document}$$1{\pi }_{{\mathrm{u}}}$$\end{document}1πu) orbitals, respectively, which is inconsistent with the predictions required for the high bond-order models of strongly \documentclass[12pt]{minimal}
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\begin{document}$$sp$$\end{document}sp-mixed orbitals. This result suggests that the dominant contribution to the dicarbon bonding involves a double-bonded configuration, with 2\documentclass[12pt]{minimal}
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\begin{document}$$\sigma$$\end{document}σ bond. In spite of its apparent simplicity, the dicarbon molecule has a bonding structure which is matter of debate. Here the authors measure high-resolution spectra of the \documentclass[12pt]{minimal}
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\begin{document}$${{\mathrm{C}}}_{2}$$\end{document}C2 anion by photoelectron imaging, revealing a bonding configuration dominated by a double \documentclass[12pt]{minimal}
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Sahlberg AL, Hot D, Lyngbye-Pedersen R, Zhou J, Aldén M, Li Z. Mid-Infrared Polarization Spectroscopy Measurements of Species Concentrations and Temperature in a Low-Pressure Flame. APPLIED SPECTROSCOPY 2019; 73:653-664. [PMID: 30556400 PMCID: PMC6557008 DOI: 10.1177/0003702818823239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 12/05/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate quantitative measurements of methane (CH4) mole fractions in a low-pressure fuel-rich premixed dimethyl ether/oxygen/argon flat flame (Φ = 1.87, 37 mbar) using mid-infrared (IR) polarization spectroscopy (IRPS). Non-intrusive in situ detection of CH4, acetylene (C2H2), and ethane (C2H6) in the flame was realized by probing the fundamental asymmetric C-H stretching vibration bands in the respective molecules in the spectral range 2970-3340 cm-1. The flame was stabilized on a McKenna-type porous plug burner hosted in a low-pressure chamber. The temperature at different heights above the burner (HAB) was measured from the line ratio of temperature-sensitive H2O spectral lines recorded using IRPS. Quantitative measurements of CH4 mole fractions at different HAB in the flame were realized by a calibration measurement in a low-pressure gas flow of N2 with a small admixture of known amount of CH4. A comprehensive study of the collision effects on the IRPS signal was performed in order to quantify the flame measurement. The concentration and temperature measurements were found to agree reasonably well with simulations using Chemkin. These measurements prove the potential of IRPS as a sensitive, non-intrusive, in situ technique in low pressure flames.
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Affiliation(s)
- Anna-Lena Sahlberg
- Anna-Lena Sahlberg, Division of Combustion Physics, Lund University, P.O. Box 118, S221 00 Lund, Sweden.
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Thomas AM, Lucas M, Zhao L, Liddiard J, Kaiser RI, Mebel AM. A combined crossed molecular beams and computational study on the formation of distinct resonantly stabilized C 5H 3 radicals via chemically activated C 5H 4 and C 6H 6 intermediates. Phys Chem Chem Phys 2018. [PMID: 29537029 DOI: 10.1039/c8cp00357b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The crossed molecular beams technique was utilized to explore the formation of three isomers of resonantly stabilized (C5H3) radicals along with their d2-substituted counterparts via the bimolecular reactions of singlet/triplet dicarbon [C2(X1Σ+g/a3Πu)] with methylacetylene [CH3CCH(X1A1)], d3-methylacetylene [CD3CCH(X1A1)], and 1-butyne [C2H5CCH(X1A')] at collision energies up to 26 kJ mol-1via chemically activated singlet/triplet C5H4/C5D3H and C6H6 intermediates. These studies exploit a newly developed supersonic dicarbon [C2(X1Σ+g/a3Πu)] beam generated via photolysis of tetrachloroethylene [C2Cl4(X1Ag)] by excluding interference from carbon atoms, which represent the dominating (interfering) species in ablation-based dicarbon sources. We evaluated the performance of the dicarbon [C2(X1Σ+g/a3Πu)] beam in reactions with methylacetylene [CH3CCH(X1A1)] and d3-methylacetylene [CD3CCH(X1A1)]; the investigations demonstrate that the reaction dynamics match previous studies in our laboratory utilizing ablation-based dicarbon sources involving the synthesis of 1,4-pentadiynyl-3 [HCCCHCCH(X2B1)] and 2,4-pentadiynyl-1 [H2CCCCCH(X2B1)] radicals via hydrogen (deuterium) atom elimination. Considering the C2(X1Σ+g/a3Πu)-1-butyne [C2H5CCH(X1A')] reaction, the hitherto elusive methyl-loss pathway was detected. This channel forms the previously unknown resonantly stabilized penta-1-yn-3,4-dienyl-1 [H2CCCHCC(X2A)] radical along with the methyl radical [CH3(X2A2'')] and is open exclusively on the triplet surface with an overall reaction energy of -86 ± 10 kJ mol-1. The preferred reaction pathways proceed first by barrierless addition of triplet dicarbon to the π-electronic system of 1-butyne, either to both acetylenic carbon atoms or to the sterically more accessible carbon atom, to form the methyl-bearing triplet C6H6 intermediates [i41b] and [i81b], respectively, with the latter decomposing via a tight exit transition state to penta-1-yn-3,4-dienyl-1 [(H2CCCHCC(X2A)] plus the methyl radical [CH3(X2A2'')]. The successful unraveling of this methyl-loss channel - through collaborative experimental and computational efforts - underscores the viability of the photolytically generated dicarbon beam as an unprecedented tool to access reaction dynamics underlying the formation of resonantly stabilized free radicals (RSFR) that are vital to molecular mass growth processes that ultimately lead to polycyclic aromatic hydrocarbons (PAHs).
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Affiliation(s)
- Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA.
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5
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Bornhauser P, Visser B, Beck M, Knopp G, van Bokhoven JA, Marquardt R, Radi PP. Experimental and theoretical investigation of the vibrational band structure of the 1 Πu5−1 Πg5 high-spin system of C2. J Chem Phys 2017; 146:114309. [DOI: 10.1063/1.4978334] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- P. Bornhauser
- Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - B. Visser
- Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - M. Beck
- Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - G. Knopp
- Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - J. A. van Bokhoven
- Paul Scherrer Institute, CH-5232 Villigen, Switzerland
- Institute for Chemical and Bioengineering, ETHZ, Zürich, Switzerland
| | - R. Marquardt
- Laboratoire de Chimie Quantique, Institut de Chimie, Université de Strasbourg 4, Rue Blaise Pascal, CS90032 67081 Strasbourg Cedex, France
| | - P. P. Radi
- Paul Scherrer Institute, CH-5232 Villigen, Switzerland
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Truscott BS, Kelly MW, Potter KJ, Ashfold MNR, Mankelevich YA. Microwave Plasma-Activated Chemical Vapor Deposition of Nitrogen-Doped Diamond. II: CH 4/N 2/H 2 Plasmas. J Phys Chem A 2016; 120:8537-8549. [PMID: 27718565 PMCID: PMC5293323 DOI: 10.1021/acs.jpca.6b09009] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a combined experimental and modeling study of microwave-activated dilute CH4/N2/H2 plasmas, as used for chemical vapor deposition (CVD) of diamond, under very similar conditions to previous studies of CH4/H2, CH4/H2/Ar, and N2/H2 gas mixtures. Using cavity ring-down spectroscopy, absolute column densities of CH(X, v = 0), CN(X, v = 0), and NH(X, v = 0) radicals in the hot plasma have been determined as functions of height, z, source gas mixing ratio, total gas pressure, p, and input power, P. Optical emission spectroscopy has been used to investigate, with respect to the same variables, the relative number densities of electronically excited species, namely, H atoms, CH, C2, CN, and NH radicals and triplet N2 molecules. The measurements have been reproduced and rationalized from first-principles by 2-D (r, z) coupled kinetic and transport modeling, and comparison between experiment and simulation has afforded a detailed understanding of C/N/H plasma-chemical reactivity and variations with process conditions and with location within the reactor. The experimentally validated simulations have been extended to much lower N2 input fractions and higher microwave powers than were probed experimentally, providing predictions for the gas-phase chemistry adjacent to the diamond surface and its variation across a wide range of conditions employed in practical diamond-growing CVD processes. The strongly bound N2 molecule is very resistant to dissociation at the input MW powers and pressures prevailing in typical diamond CVD reactors, but its chemical reactivity is boosted through energy pooling in its lowest-lying (metastable) triplet state and subsequent reactions with H atoms. For a CH4 input mole fraction of 4%, with N2 present at 1-6000 ppm, at pressure p = 150 Torr, and with applied microwave power P = 1.5 kW, the near-substrate gas-phase N atom concentration, [N]ns, scales linearly with the N2 input mole fraction and exceeds the concentrations [NH]ns, [NH2]ns, and [CN]ns of other reactive nitrogen-containing species by up to an order of magnitude. The ratio [N]ns/[CH3]ns scales proportionally with (but is 102-103 times smaller than) the ratio of the N2 to CH4 input mole fractions for the given values of p and P, but [N]ns/[CN]ns decreases (and thus the potential importance of CN in contributing to N-doped diamond growth increases) as p and P increase. Possible insights regarding the well-documented effects of trace N2 additions on the growth rates and morphologies of diamond films formed by CVD using MW-activated CH4/H2 gas mixtures are briefly considered.
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Affiliation(s)
| | - Mark W Kelly
- School of Chemistry, University of Bristol , Bristol BS8 1TS, U.K
| | - Katie J Potter
- School of Chemistry, University of Bristol , Bristol BS8 1TS, U.K
| | | | - Yuri A Mankelevich
- Skobel'tsyn Institute of Nuclear Physics, Moscow State University , Leninskie gory, Moscow 119991, Russia.,Institute of Applied Physics, IAP RAS , 46 Ulyanov st., Nizhny Novgorod 603950, Russia
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7
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Bacalla X, Salumbides EJ, Linnartz H, Ubachs W, Zhao D. Spectroscopic Survey of Electronic Transitions of C6H, (13)C6H, and C6D. J Phys Chem A 2016; 120:6402-17. [PMID: 27459295 DOI: 10.1021/acs.jpca.6b06647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xavier Bacalla
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit Amsterdam , De Boelelaan 1081, NL-1081 HV Amsterdam, The Netherlands.,Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University , P.O. Box 9513, NL-2300 RA Leiden, The Netherlands
| | - Edcel J Salumbides
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit Amsterdam , De Boelelaan 1081, NL-1081 HV Amsterdam, The Netherlands.,Department of Physics, University of San Carlos , Nasipit, Talamban, Cebu City 6000, Philippines
| | - Harold Linnartz
- Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University , P.O. Box 9513, NL-2300 RA Leiden, The Netherlands
| | - Wim Ubachs
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit Amsterdam , De Boelelaan 1081, NL-1081 HV Amsterdam, The Netherlands
| | - Dongfeng Zhao
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit Amsterdam , De Boelelaan 1081, NL-1081 HV Amsterdam, The Netherlands.,Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University , P.O. Box 9513, NL-2300 RA Leiden, The Netherlands
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Abstract
The unstable molecule C₂ has been of interest since its identification as the source of the "Swan band" features observable in the spectra offlames, carbon arcs, white dwarf stars, and comets, and it continues to serve as a focal point for experimental and theoretical discovery. Recent spectroscopic work has identified a quintet state of the molecule for the first time, while new insights into the bond order of C₂ in its ground state have been provided by sophisticated computational methods based on valence bond theory. This article gives a review of spectroscopic and computational work on C₂ including both historical background and the most recent discoveries.
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Ruscic B, Feller D, Peterson KA. Active Thermochemical Tables: dissociation energies of several homonuclear first-row diatomics and related thermochemical values. Theor Chem Acc 2013. [DOI: 10.1007/s00214-013-1415-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Bornhauser P, Sych Y, Knopp G, Gerber T, Radi PP. Shedding light on a dark state: the energetically lowest quintet state of C2. J Chem Phys 2011; 134:044302. [PMID: 21280720 DOI: 10.1063/1.3526747] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work we present a deperturbation study of the d (3)Π(g), v=6 state of C(2) by double-resonant four-wave mixing spectroscopy. Accurate line positions of perturbed transitions are unambiguously assigned by intermediate level labeling. In addition, extra lines are accessible by taking advantage of the sensitivity and high dynamic range of the technique. These weak spectral features originate from nearby-lying dark states that gain transition strength through the perturbation process. The deperturbation analysis of the complex spectral region in the (6,5) and (6,4) bands of the Swan system (d(3)Π(g)-a (3)Π(u)) unveils the presence of the energetically lowest high-spin state of C(2) in the vicinity of the d (3)Π(g), v=6 state. The term energy curves of the three spin components of the d state cross the five terms of the 1 (5)Π(g) state at rotational quantum numbers N ≤ 11. The spectral complexity for transitions to the v = 6 level of d (3)Π(g) state is further enhanced by an additional perturbation at N = 19 and 21 owing to the b (3)Σ(g)(-), v=19 state. The spectroscopic characterization of both dark states is accessible by the measurement of 122 "window" levels. A global fit of the positions to a conventional Hamiltonian for a linear diatomic molecule yields accurate molecular constants for the quintet and triplet perturber states for the first time. In addition, parameters for the spin-orbit and L-uncoupling interaction between the electronic levels are determined. The detailed deperturbation study unravels major issues of the so-called high-pressure bands of C(2). The anomalous nonthermal emission initially observed by Fowler in 1910 [Mon. Not. R. Astron. Soc. 70, 484 (1910)] and later observed in numerous experimental environments are rationalized by taking into account "gateway" states, i.e., rotational levels of the d (3)Π(g), v=6 state that exhibit significant (5)Π(g) character through which all population flows from one electronic state to the other.
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Affiliation(s)
- P Bornhauser
- Paul Scherrer Institute, General Energy Department, CH-5232 Villigen, Switzerland
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13
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Mazzotti FJ, Achkasova E, Chauhan R, Tulej M, Radi PP, Maier JP. Electronic spectra of radicals in a supersonic slit-jet discharge by degenerate and two-color four-wave mixing. Phys Chem Chem Phys 2008; 10:136-41. [DOI: 10.1039/b712737e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Brockhinke A, Letzgus M, Rinne S, Kohse-Höinghaus K. Energy Transfer in the d3Πg−a3Πu (0−0) Swan Bands of C2: Implications for Quantitative Measurements. J Phys Chem A 2006; 110:3028-35. [PMID: 16509624 DOI: 10.1021/jp055553g] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Energy transfer effects on dicarbon (C2) d3Pi(g) <-- a3Pi(u) laser-induced fluorescence (LIF) spectra in fuel-rich acetylene atmospheric-pressure flames have been studied using a combination of two different two-dimensional techniques. Measurements using a picosecond laser system in conjunction with a streak camera allowed determination of typical fluorescence lifetimes of levels in the d state and of population changes introduced by rotational energy transfer (RET) and by state-dependent quenching. Excitation-emission spectroscopy yielded two-dimensional maps containing all excitation and all emission spectra in the spectral ranges between 19 340 and 20 150 cm(-1) (excitation) and from 546 to 573 nm (emission) and allowed unambiguous assignment of all transitions in this spectral region. Our measurements show a comparatively long quenching lifetime (around 2 ns) and dominant effects of energy transfer on shape and intensity of the acquired spectra (90% of the fluorescence stems from levels populated by ET). A pronounced dependence of the total RET on the quantum number of the initially excited state is observed. Vibrational energy transfer (VET) is significantly weaker (only 5% contribution for excitation in the v' = 1 level). Implications for quantitative concentration measurements are discussed, and exemplary spatially resolved profiles in a well-characterized low-pressure propene flame are presented.
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Affiliation(s)
- A Brockhinke
- Physikalische Chemie 1, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, Bielefeld D-33615, Germany
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Abstract
The ability to separate and sort peaks is explored using a new coherent two-dimensional form of resonance Raman spectroscopy. This experimental technique distributes normally congested rotational-vibrational peaks along a series of curved lines according to vibrational sequence, rotational quantum number, and selection rule. Each line consists of rotational-vibrational peaks that have the same vibrational sequence and the same value for DeltaJ, distributed in order by rotational quantum number. For diatomic molecules, these lines originate from points where they initially travel in opposite or orthogonal directions in two-dimensional space, which helps facilitate the separation between lines. Simulations and experimental results on C2 in a flame confirm the ability to separate and sort these normally congested rotational-vibrational peaks. This method appears to provide a solution to the long-standing problems of spectral congestion and disorder in gas-phase electronic spectra.
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Affiliation(s)
- Peter C Chen
- Chemistry Department, Spelman College, 350 Spelman Lane, Atlanta, Georgia 30314, USA.
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Araki M, Cias P, Denisov A, Fulara J, Maier JP. Electronic spectroscopy of the nonlinear carbon chains C4H4+ and C8H4+. CAN J CHEM 2004. [DOI: 10.1139/v04-013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The electronic spectrum of a nonlinear carbon chain radical C4H4+ was observed after mass-selective deposition in a 6 K neon matrix. The corresponding gas-phase spectra of C4H4+ and C4D4+ have been observed in the 512 to 513 nm region and at 710 nm for C8H4+. These were detected in direct absorption by cavity ringdown spectroscopy through a supersonic planar discharge. The electronic transition energies of these nonlinear carbon chain radicals correlate well with those of the polyacetylene cations HCnH+ (n = 4, 6, 8). The observed profiles are reproduced with rotational constants obtained by ab initio geometry optimizations and extrapolation between the ground and excited electronic states. Key words: nonlinear carbon chain, carbon cation, electronic transition, diffuse interstellar bands, molecular structure.
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Rennick C, Smith J, Ashfold M, Orr-Ewing A. Cavity ring-down spectroscopy measurements of the concentrations of C2(X1Σg+) radicals in a DC arc jet reactor used for chemical vapour deposition of diamond films. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2003.11.089] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Tellinghuisen J. Direct-fitting approach to the analysis of high-resolution optical spectra: Monte Carlo and experimental studies of OH A(0)→X(0) spectra. J Chem Phys 2001. [DOI: 10.1063/1.1342226] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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