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Dore L, Bizzocchi L, Lattanzi V, Melosso M, Tamassia F, McCarthy MC. First Laboratory Detection of N 13CO - and Semiexperimental Equilibrium Structure of the NCO - Anion. J Phys Chem A 2022; 126:1899-1904. [PMID: 35285635 PMCID: PMC8958587 DOI: 10.1021/acs.jpca.2c00313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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The cyanate anion
(NCO–) is a species of considerable
astrophysical relevance. It is widely believed to be embedded in interstellar
ices present in young stellar objects but has not yet been detected
in the dense gas of the interstellar medium. Here we report highly
accurate laboratory measurements of the rotational spectrum of the
N13CO– isotopologue at submillimeter
wavelengths along with the detection of three additional lines of
the parent isotopologue up to 437.4 GHz. With this new data, the rotational
spectrum of both isotopologues can be predicted to better 0.25 km
s–1 in equivalent radial velocity up to 1 THz, more
than adequate for an astronomical search in any source. Moreover,
a semiexperimental equilibrium structure of the anion is derived by
combining the experimental ground-state rotational constants of the
two isotopologues with theoretical vibrational corrections, obtained
by using the coupled-cluster method with inclusion of single and double
excitations and perturbative inclusion of triple excitations (CCSD(T)).
The estimated accuracy of the two bond distances is on the order of
5 × 10–4 Å: a comparison to the values
obtained by geometry optimization with the CCSD(T) method and the
use of a composite scheme, including additivity and basis-set extrapolation
techniques, reveals that this theoretical procedure is very accurate.
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Affiliation(s)
- Luca Dore
- Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy
| | - Luca Bizzocchi
- Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy
| | - Valerio Lattanzi
- Center for Astrochemical Studies, Max Planck Institut für Extraterrestrische Physik Gießenbachstraße 1, D-85748 Garching bei München, Germany
| | - Mattia Melosso
- Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy.,Scuola Superiore Meridionale, Università di Napoli Federico II, Largo San Marcellino 10, I-80138 Naples, Italy
| | - Filippo Tamassia
- Dipartimento di Chimica Industriale "Toso Montanari", Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
| | - Michael C McCarthy
- Center for Astrophysics
- Harvard & Smithsonian, 60 Garden St., Cambridge, Massachusetts 02138, United States
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Wehrli D, Génévriez M, Knecht S, Reiher M, Merkt F. Complete characterization of the 3p Rydberg complex of a molecular ion: MgAr+. I. Observation of the Mg(3pσ)Ar+ B+ state and determination of its structure and dynamics. J Chem Phys 2020; 153:074310. [DOI: 10.1063/5.0015603] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Dominik Wehrli
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Matthieu Génévriez
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Stefan Knecht
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Markus Reiher
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Frédéric Merkt
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
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3
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Génévriez M, Wehrli D, Merkt F. Complete characterization of the 3p Rydberg complex of a molecular ion: MgAr+. II. Global analysis of the A+ 2Π and B+ 2Σ+ (3pσ,π) states. J Chem Phys 2020; 153:074311. [DOI: 10.1063/5.0015608] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Matthieu Génévriez
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Dominik Wehrli
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Frédéric Merkt
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
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4
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Li B, Wang L, Fang B, Zhao WX, Deng LH, Xu HL. Population change of OH and H2O in water vapor glow discharge measured using concentration modulation spectroscopy. CHINESE J CHEM PHYS 2020. [DOI: 10.1063/1674-0068/cjcp2001010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Bao Li
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Li Wang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Bo Fang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Wei-xiong Zhao
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Lun-hua Deng
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Huai-liang Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
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5
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Guan YC, Chang YH, Liao YC, Peng JL, Wang LB, Shy JT. Precision saturated absorption spectroscopy of H 3. J Chem Phys 2018; 148:124310. [PMID: 29604856 DOI: 10.1063/1.5017080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In our previous work on the Lamb-dips of the ν2 fundamental band transitions of H3+, the saturated absorption spectrum was obtained by third-derivative spectroscopy using frequency modulation with an optical parametric oscillator (OPO). However, frequency modulation also caused errors in the absolute frequency determination. To solve this problem, we built a tunable offset locking system to lock the pump frequency of the OPO to an iodine-stabilized Nd:YAG laser. With this improvement, we were able to scan the OPO idler frequency precisely and obtain the saturated absorption profile using intensity modulation. Furthermore, ion concentration modulation was employed to subtract the background noise and increase the signal-to-noise ratio. To determine the absolute frequency of the idler wave, the OPO signal frequency was locked to an optical frequency comb. The absolute frequency accuracy of our spectrometer was better than 7 kHz, demonstrated by measuring the wavelength standard transition of methane at 3.39 μm. Finally, we measured 16 transitions of H3+ and our results agree very well with other precision measurements. This work successfully resolved the discrepancies between our previous measurements and other precision measurements.
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Affiliation(s)
- Yu-Chan Guan
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yung-Hsiang Chang
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yi-Chieh Liao
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Jin-Long Peng
- Center for Measurement Standards, Industrial Technology Research Institute, Hsinchu 30011, Taiwan
| | - Li-Bang Wang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Jow-Tsong Shy
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan
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6
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Jacovella U, Agner JA, Schmutz H, Deiglmayr J, Merkt F. Infrared spectroscopy of molecular ions in selected rotational and spin-orbit states. J Chem Phys 2016; 145:014301. [DOI: 10.1063/1.4954701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- U. Jacovella
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
| | - J. A. Agner
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
| | - H. Schmutz
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
| | - J. Deiglmayr
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
| | - F. Merkt
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
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7
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Hodges JN, McCall BJ. Quantitative velocity modulation spectroscopy. J Chem Phys 2016; 144:184201. [DOI: 10.1063/1.4948740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- James N. Hodges
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
| | - Benjamin J. McCall
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
- Departments of Physics and Astronomy, University of Illinois, Urbana, Illinois 61801, USA
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8
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Liu HT, Ning CG, Huang DL, Wang LS. Vibrational Spectroscopy of the Dehydrogenated Uracil Radical by Autodetachment of Dipole-Bound Excited States of Cold Anions. Angew Chem Int Ed Engl 2014; 53:2464-8. [DOI: 10.1002/anie.201310323] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Indexed: 01/29/2023]
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9
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Liu HT, Ning CG, Huang DL, Wang LS. Vibrational Spectroscopy of the Dehydrogenated Uracil Radical by Autodetachment of Dipole-Bound Excited States of Cold Anions. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201310323] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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10
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Hodges JN, Perry AJ, Jenkins PA, Siller BM, McCall BJ. High-precision and high-accuracy rovibrational spectroscopy of molecular ions. J Chem Phys 2013; 139:164201. [DOI: 10.1063/1.4825251] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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11
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Neese CF, Kreynin PS, Oka T. Hot Band Spectroscopy of the Formyl Cation, H12C16O+. J Phys Chem A 2013; 117:9899-907. [DOI: 10.1021/jp312879f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Christopher F. Neese
- Department of Chemistry and the Enrico Fermi
Institute, University of Chicago, Chicago,
Illinois 60637, United States
| | - Peter S. Kreynin
- Physics, School of Natural Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne
NE1 7RU, U.K
| | - Takeshi Oka
- Department of Chemistry and the Enrico Fermi
Institute, University of Chicago, Chicago,
Illinois 60637, United States
- Department of Astronomy & Astrophysics, University of Chicago, Chicago, Illinois 60637, United States
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12
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Affiliation(s)
- Michael A. Duncan
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United
States
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13
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Crabtree KN, Hodges JN, Siller BM, Perry AJ, Kelly JE, Jenkins PA, McCall BJ. Sub-Doppler mid-infrared spectroscopy of molecular ions. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.09.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Broadband velocity modulation spectroscopy of HfF+: Towards a measurement of the electron electric dipole moment. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.06.037] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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15
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Mills AA, Siller BM, Porambo MW, Perera M, Kreckel H, McCall BJ. Ultra-sensitive high-precision spectroscopy of a fast molecular ion beam. J Chem Phys 2011; 135:224201. [DOI: 10.1063/1.3665925] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Siller BM, Porambo MW, Mills AA, McCall BJ. Noise immune cavity enhanced optical heterodyne velocity modulation spectroscopy. OPTICS EXPRESS 2011; 19:24822-24827. [PMID: 22109511 DOI: 10.1364/oe.19.024822] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The novel technique of cavity enhanced velocity modulation spectroscopy has recently been demonstrated as the first general absorption technique that allows for sub-Doppler spectroscopy of molecular ions while retaining ion-neutral discrimination. The previous experimental setup has been further improved with the addition of heterodyne detection in a NICE-OHMS setup. This improves the sensitivity by a factor of 50 while retaining sub-Doppler resolution and ion-neutral discrimination. Calibration was done with an optical frequency comb, and line centers for several N(2)(+) lines have been determined to within an accuracy of 300 kHz.
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Affiliation(s)
- Brian M Siller
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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17
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Sinclair LC, Cossel KC, Coffey T, Ye J, Cornell EA. Frequency comb velocity-modulation spectroscopy. PHYSICAL REVIEW LETTERS 2011; 107:093002. [PMID: 21929235 DOI: 10.1103/physrevlett.107.093002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Indexed: 05/31/2023]
Abstract
We have demonstrated a new technique that provides massively parallel comb spectroscopy sensitive specifically to ions through the combination of cavity-enhanced direct frequency comb spectroscopy with velocity-modulation spectroscopy. Using this novel system, we have measured electronic transitions of HfF⁺ and achieved a fractional absorption sensitivity of 3×10⁻⁷ recorded over 1500 simultaneous channels spanning 150 cm⁻¹ around 800 nm with an absolute frequency accuracy of 30 MHz (0.001 cm⁻¹). A fully sampled spectrum consisting of interleaved measurements is acquired in 30 min.
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Affiliation(s)
- Laura C Sinclair
- JILA, National Institute of Standards and Technology and University of Colorado Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA.
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19
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Crabtree KN, Kauffman CA, McCall BJ. Note: A modular and robust continuous supersonic expansion discharge source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:086103. [PMID: 20815632 DOI: 10.1063/1.3478019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A direct current discharge has been coupled with a continuous supersonic expansion to provide a source of rotationally cold molecular ions for gas phase spectroscopy. Constructed primarily of machinable ceramic and stainless steel, this source design is modular, customizable, and robust. Its performance has been assessed by recording transitions within the nu(2) fundamental band of H(3) (+) using cavity ringdown spectroscopy to determine the rotational temperature of ions produced in the free-jet expansion. Temperature and column density were recorded as a function of discharge current as the source was operated over a period of 200 h. Observed temperatures ranged between 50-110 K, and the ion column densities between 8x10(10) and 2x10(12) cm(-2).
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Affiliation(s)
- Kyle N Crabtree
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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20
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Baer T, Dunbar RC. Ion spectroscopy: where did it come from; where is it now; and where is it going? JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2010; 21:681-693. [PMID: 20189827 DOI: 10.1016/j.jasms.2010.01.028] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 01/27/2010] [Accepted: 01/27/2010] [Indexed: 05/28/2023]
Abstract
The ASMS conference on ion spectroscopy brought together at Asilomar on October 16-20, 2009 a large group of mass spectrometrists working in the area of ion spectroscopy. In this introduction to the field, we provide a brief history, its current state, and where it is going. Ion spectroscopy of intermediate size molecules began with photoelectron spectroscopy in the 1960s, while electronic spectroscopy of ions using the photodissociation "action spectroscopic" mode became active in the next decade. These approaches remained for many years the main source of information about ionization energies, electronic states, and electronic transitions of ions. In recent years, high-resolution laser techniques coupled with pulsed field ionization and sample cooling in molecular beams have provided high precision ionization energies and vibrational frequencies of small to intermediate sized molecules, including a number of radicals. More recently, optical parametric oscillator (OPO) IR lasers and free electron lasers have been developed and employed to record the IR spectra of molecular ions in either molecular beams or ion traps. These results, in combination with theoretical ab initio molecular orbital (MO) methods, are providing unprecedented structural and energetic information about gas-phase ions.
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Affiliation(s)
- Tomas Baer
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA.
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21
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Siller BM, Mills AA, McCall BJ. Cavity-enhanced velocity modulation spectroscopy. OPTICS LETTERS 2010; 35:1266-1268. [PMID: 20410988 DOI: 10.1364/ol.35.001266] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The spectroscopic study of molecular ions is of great importance to a variety of fields, but is challenging as ions are typically produced in plasmas containing many orders of magnitude more neutral molecules than ions. The successful technique of velocity modulation permits discrimination between ion and neutral absorption signals and has allowed the study of scores of molecular ions in the past quarter century. However, this technique has long been considered to be inappropriate for use with cavity-enhanced techniques, owing to the directional nature of the velocity modulation. Here we report what we believe to be the first demonstration of cavity-enhanced velocity modulation spectroscopy, utilizing a 2f phase-sensitive demodulation scheme. This approach offers the promise of combining very high-sensitivity spectroscopic techniques with ion-neutral discrimination, which could extend the applicability of velocity modulation to intrinsically weak transitions and to ions that cannot be produced in high abundance. The use of a cavity also permits Lamb dip spectroscopy, which offers higher resolution and precision in frequency measurements and may be useful in measuring collisional rate coefficients.
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Affiliation(s)
- Brian M Siller
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue,Urbana, Illinois 61801, USA
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22
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Terasaki A, Majima T, Kondow T. Photon-trap spectroscopy of mass-selected ions in an ion trap: Optical absorption and magneto-optical effects. J Chem Phys 2007; 127:231101. [DOI: 10.1063/1.2822022] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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23
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Gottlieb CA, Brünken S, McCarthy MC, Thaddeus P. The rotational spectrum of CN−. J Chem Phys 2007; 126:191101. [PMID: 17523781 DOI: 10.1063/1.2737442] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The rotational spectrum of the molecular negative ion CN(-) has been detected in the laboratory at high resolution. The four lowest transitions were observed in a low pressure glow discharge through C(2)N(2) and N(2). Conclusive evidence for the identification was provided by well-resolved nitrogen quadrupole hyperfine structure in the lowest rotational transition, and a measurable Doppler shift owing to ion drift in the positive column of the discharge. Three spectroscopic constants (B, D, and eQq) reproduce the observed spectrum to within one part in 10(7) or better, allowing the entire rotational spectrum to be calculated well into the far IR to within 1 km s(-1) in equivalent radial velocity. CN(-) is an excellent candidate for astronomical detection, because the CN radical is observed in many galactic molecular sources, the electron binding energy of CN(-) is large, and calculations indicate CN(-) should be detectable in IRC+10216-the carbon star where C(6)H(-) has recently been observed. The fairly high concentration of CN(-) in the discharge implies that other molecular anions containing the nitrile group may be within reach.
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Affiliation(s)
- C A Gottlieb
- Harvard-Smithsonian Center for Astrophysics, Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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24
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Chiavarino B, Crestoni ME, Fornarini S, Lemaire J, Maître P, MacAleese L. π-Complex Structure of Gaseous Benzene−NO Cations Assayed by IR Multiple Photon Dissociation Spectroscopy. J Am Chem Soc 2006; 128:12553-61. [PMID: 16984206 DOI: 10.1021/ja0637548] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[C(6)H(6)NO](+) ions, in two isomeric forms involved as key intermediates in the aromatic nitrosation reaction, have been produced in the gas phase and analyzed by IR multiple photon dissociation (IRMPD) spectroscopy in the 800-2200 cm(-)(1) fingerprint wavenumber range, exploiting the high fluence and wide tunability of a free electron laser (FEL) source. The IRMPD spectra were compared with the IR absorption spectra calculated for the optimized structures of potential isomers, thus allowing structural information on the absorbing species. [C(6)H(6)NO](+) ions were obtained by two routes, taking advantage of the FEL coupling to two different ion traps. In the first one, an FT-ICR mass spectrometer, a sequence of ion-molecule reactions was allowed to occur, ultimately leading to an NO(+) transfer process to benzene. The so-formed ions displayed IRMPD features characteristic of a [benzene,NO](+) pi-complex structure, including a prominent band at 1963 cm(-)(1), within the range for the N-O bond stretching vibration of NO (1876 cm(-)(1)) and NO(+) (2344 cm(-)(1)). A quite distinct species is formed by electrospray ionization (ESI) of a methanol solution of nitrosobenzene. The ions transferred and stored in a Paul ion trap showed the IRMPD features of substituent protonated nitrosobenzene, the most stable among conceivable [C(6)H(6)NO](+) isomers according to computations. It is noteworthy that IRMPD is successful in allowing a discrimination between isomeric [C(6)H(6)NO](+) species, whereas high-energy collision-induced dissociation fails in this task. The [benzene,NO](+) pi-complex is characterized by IRMPD spectroscopy as an exemplary noncovalent ionic adduct between two important biomolecular moieties.
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Affiliation(s)
- Barbara Chiavarino
- Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Università di Roma La Sapienza, I-00185 Roma, Italy
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Schofield K. An Overlooked Series of Gas Phase Diatomic Metal Oxide Ions that Are Long-lived. J Phys Chem A 2006; 110:6938-47. [PMID: 16722708 DOI: 10.1021/jp0564187] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Although the "Golden" years of spectroscopy and the major studies on ionization processes now are behind us, as with many branches of science, much yet remains to be gleaned from such topics that is both full of interest and of significance to present day research. Presented here is one such overlooked example, an observation that relates to both these fields. An analysis is presented for the periodic table concerning the gas-phase thermochemical nature of MO+ and MO2+ ions. Unexpectedly, a pattern of 18 elements has been identified that exhibit the potential for having long-lived MO+ ions. Normally such molecular ions are expected to decay extremely rapidly by dissociative recombination with electrons, but in particular, 12 of this group behave not like molecules but rather as atomic ions. These are the diatomic oxide ions of Sc, Y, La, Zr, Hf, Ce, Pr, Nd, Pm, Gd, Tb, and Th. In the gas phase, they decay by much slower three-body recombination channels. As may be noted, these elements are located in the first two columns of the transition elements, among the earlier rare earths and an actinide. From all the elements, UO2+ is the only dioxide ion that behaves similarly. These findings now elevate the potential importance of these ions and should facilitate their spectral characterization. Moreover, subsequent comparisons with spectra of well-known isoelectronic and isovalent neutral monoxides and other diatomics will help in the stimulation of further theoretical advances. In addition, once characterized, an ease of spectrally monitoring such ionic states will provide a useful analytical tool.
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Affiliation(s)
- Keith Schofield
- Materials Research Laboratory, University of California, Santa Barbara, California 93106-5121, USA.
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