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High-resolution infrared spectroscopy of supersonically cooled singlet carbenes: Bromomethylene (HCBr) in the CH stretch region

Journal Article · · Journal of Chemical Physics
DOI:https://doi.org/10.1063/5.0077341· OSTI ID:1924524
 [1];  [2];  [3]
  1. Univ. of Colorado, Boulder, CO (United States); National Inst. of Standards and Technology (NIST), Boulder, CO (United States); JILA/Department of Chemistry
  2. Cold Quanta, Boulder, CO (United States)
  3. Univ. of Colorado, Boulder, CO (United States); National Inst. of Standards and Technology (NIST), Boulder, CO (United States)
First high-resolution spectra of cold (~35 K) singlet bromomethylene HCBr in the CH stretching (v1) region from 2770 to 2850 cm-1 are reported using near quantum shot-noise limited laser absorption methods in a slit jet supersonic discharge expansion source. Three rovibrational bands are identified at high S/N (20:1 - 40:1) and rotationally assigned to i) the CH stretch fundamental (v1) band $$\tilde{X}$$(1,0,0) ← $$\tilde{X}$$ (0,0,0) and ii) vibrational hot bands ($$\tilde{X}$$(1,1,0) ← $$\tilde{X}$$(0,1,0) and $$\tilde{X}$$(1,0,1) ← $$\tilde{X}$$(0,0,1)) arising from vibrationally excited HCBr populated in the discharge with single quanta in either the H–C–Br bend (v2) or C–Br stretch (v3) modes. Precision rotational constants are reported for a total of six states, with an experimentally determined CH stretch vibrational frequency (2799.38 cm-1) in good agreement with previous low-resolution fluorescence studies. Detailed analysis of the fundamental v1 band highlights the presence of perturbations in the $$\tilde{X}$$(1,0,0) level, which we tentatively attribute to arise from the nearby triplet state $$\tilde{a}$$(0,0,1) through spin-orbit interaction or the multiple quanta $$\tilde{X}$$(0,2,1) singlet state via c-type Coriolis coupling. Reduced-Doppler resolution (60 MHz) in the slit-jet IR spectrometer permits clear observation of nuclear spin hyperfine structure, with experimental line shapes well reproduced by nuclear quadrupole/spin-rotation coupling constants from microwave studies. Lastly, the a-type to b-type transition intensity ratio for the fundamental CH stretch band is notably larger than predicted by a bond-dipole model, which from high level ab initio quantum calculations (CCSD(T)/PVQZ) can be attributed to vibrationally induced “charge-sloshing” of electron density along the polar C–Br bond.
Research Organization:
University of Colorado, Boulder, CO (United States)
Sponsoring Organization:
National Science Foundation (NSF); USDOE
Contributing Organization:
NSF(CHE, PHYS)
Grant/Contract Number:
SC0002123
OSTI ID:
1924524
Alternate ID(s):
OSTI ID: 1838207
Journal Information:
Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 1 Vol. 156; ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English

References (56)

Bismacrocyclic Inhibitors of Hepatitis C NS3/4a Protease journal November 2008
Rotationally Resolved Near-Infrared Spectrum of the HCCI Ã1A″ ← X̃1A′ Transition journal October 1995
Near-Infrared Spectroscopy of Bromomethylene in a Slit-Jet Expansion journal July 2000
Zur Theorie der Wechselwirkung zwischen Elektronen- und Kernbewegung bei dreiatomigen, stabf�rmigen Molek�len journal March 1934
Methylene: ab initio vibronic analysis and reinterpretation of the spectroscopic and negative ion photoelectron experiments journal April 1978
Lifetime lengthening and the Renner–Teller effect in the HCF (Ã1A″←X̃1A′) system journal September 2003
New dispersed fluorescence spectra of HCBr and DCBr journal September 2005
An experimental and theoretical study on rotational constants of vibrationally excited CH2OO journal February 2015
Enhancement of infrared activity by moving electrons through bonds – The case of CO2 anion and carboxylate journal September 2017
High-resolution infrared spectra of vibrationally excited HC4H in a supersonic hydrocarbon plasma jet journal February 2014
PGOPHER: A program for simulating rotational, vibrational and electronic spectra journal January 2017
Concentration modulation spectroscopy with a pulsed slit supersonic discharge expansion source journal August 2001
Ab initio potential energy surface and vibrational frequencies of Ã(1A″) HCF journal July 1998
Hot bands in the spectrum of HCBr journal May 2003
Rotational spectrum of HCBr produced by 193-nm laser photolysis of bromoform journal July 2003
Collision-induced energy flow between vibrational modes of small polyatomic molecules journal November 1981
Negative ion photoelectron spectroscopy of halocarbene anions (HCF-, HCCl-, HCBr-, and HCI-); photoelectron angular distributions and neutral triplet excitation energies journal February 1992
Collision-induced vibrational energy transfer in small polyatomic molecules journal November 1987
The Reactivity of Methylene from Photolysis of Diazomethane journal September 1960
Indiscriminate Reaction of Methylene with the Carbon-Hydrogen bond journal July 1956
Total Synthesis of Iejimalide A−D and Assessment of the Remarkable Actin-Depolymerizing Capacity of These Polyene Macrolides journal June 2007
Catalytic Asymmetric C−H Activation of Alkanes and Tetrahydrofuran journal March 2000
Photodissociation of Bromoform at 248 nm:  Single and Multiphoton Processes journal March 2004
Prying Apart a Water Molecule with Anionic H-Bonding:  A Comparative Spectroscopic Study of the X - ·H 2 O (X = OH, O, F, Cl, and Br) Binary Complexes in the 600−3800 cm -1 Region journal April 2006
The Role of Electrical Anharmonicity in the Association Band in the Water Spectrum journal April 2014
Anharmonicities and Isotopic Effects in the Vibrational Spectra of X ·H 2 O, ·HDO, and ·D 2 O [X = Cl, Br, and I] Binary Complexes journal January 2010
Role of Spin−Orbit Coupling and Symmetry in Triplet Carbenic Addition Chemistry journal January 1996
First observation of the elusive iodocarbene: ground state multiplicity and singlet–triplet gap of CHI journal January 2008
Vibrational manifestations of strong non-Condon effects in the H3O+·X3 (X = Ar, N2, CH4, H2O) complexes: A possible explanation for the intensity in the “association band” in the vibrational spectrum of water journal January 2012
Stabilization and precise calibration of a continuous‐wave difference frequency spectrometer by use of a simple transfer cavity journal January 1994
Laser excitation and dispersed fluorescence spectra of the HCBr ÖX̃ vibronic transition journal July 2001
Experimental and theoretical studies of the near-infrared spectrum of bromomethylene journal September 2001
Angular momentum dependence of first‐ and second‐order singlet‐triplet interactions in polyatomic molecules journal April 1973
New electronic spectra of the HCCl and DCCl Ã-X̃ vibronic bands journal September 2004
Vibrational excitation and relaxation of five polyatomic molecules in an electrical discharge journal May 2005
Fluorescence excitation and emission spectroscopy of the ÃA″1←X̃A′1 system of CHBr journal April 2006
Fluorescence excitation and single vibronic level emission spectroscopy of the ÃA″1←X̃A′1 system of CHCl journal June 2006
High-resolution infrared studies in slit supersonic discharges: CH2 stretch excitation of jet-cooled CH2Cl radical journal August 2006
High resolution study of spin-orbit mixing and the singlet-triplet gap in chlorocarbene: Stimulated emission pumping spectroscopy of CH35Cl and CD35Cl journal September 2008
Magnetic properties of the A ̃  1 A ″ state of HCF journal May 1984
Methylene: A study of the X ̃  3 B 1 and a ̃  1 A 1 states by photoelectron spectroscopy of CH 2 and CD 2 journal November 1985
Visible absorption and magnetic‐rotation spectroscopy of 1 CH 2 : Analysis of the 1 A 1 state and the 1 A 13 B 1 coupling journal February 1987
Direct IR laser absorption spectroscopy of jet‐cooled CO 2 HF complexes: Analysis of the ν 1 HF stretch and a surprisingly low frequency ν 6 intermolecular CO 2 bend journal May 1987
Rigid bender analysis of van der Waals complexes: The intermolecular bending potential of a hydrogen bond journal April 1992
High resolution near‐infrared electronic spectroscopy of HCBr journal August 1996
Towards a global model of spin-orbit coupling in the halocarbenes journal June 2015
High-resolution sub-Doppler infrared spectroscopy of atmospherically relevant Criegee precursor CH 2 I radicals: CH 2 stretch vibrations and “charge-sloshing” dynamics journal May 2018
High-resolution infrared spectroscopy of HCF in the CH stretch region journal January 2020
Coupled-cluster techniques for computational chemistry: The CFOUR program package journal June 2020
The halocarbenes: model systems for understanding the spectroscopy, dynamics and chemistry of carbenes journal July 2009
High-resolution determination of the electron affinity of fluorine and bromine using crossed ion and laser beams journal October 1989
Quantum Variational Calculations for a Range of C H 2 Configurations journal April 1960
Divalent Carbon Intermediates: Laser Photolysis and Spectroscopy journal September 1984
Methylene: A Paradigm for Computational Quantum Chemistry journal March 1986
High-resolution methane ν_3-band spectra using a stabilized tunable difference-frequency laser system* journal January 1976
A Molecular Beam Microwave Fourier Transform (MB-MWFT) Spectrometer with an Electric Discharge Nozzle journal October 1991