A matrix isolation ESR investigation of the MgCH radical

Thomas S. Hearne, Emmanuel Karakyriakos, Cara L. Dunford, Marcus Kettner, Duncan A. Wild, Allan J. McKinley

Research output: Contribution to journalArticle

Abstract

The MgCH radical and its magnesium-25, carbon-13, and deuterated isotopologs have been isolated in low temperature neon matrices and examined by the matrix isolation electron spin resonance technique for the first time. The radicals were formed through the reactions of laser ablated natural abundance magnesium metal and magnesium-25 enriched magnesium metal with carbon-13 and deuterated isotopologs of acetone. The MgCH radical was shown to have a X4ς- ground electronic state, and the magnetic parameters determined for this state were g = 2.001 81(45), g = 2.0018(10), D = 4970(5) MHz, A(13C) = 115(6) MHz, A(13C) = 65(15) MHz, A(H) = 34(6) MHz, A(H) = 5(10) MHz, A(D) = 5(3) MHz, A(25Mg) = 82(5) MHz, and A(25Mg) = 85(10). Comparisons are made between the electronic structure of this radical and the MgCH3 and MgN radicals. Theoretical hyperfine parameters were also evaluated for the MgCH radical, and a potential energy surface for the low-lying electronic states was constructed using complete active space multiconfigurational self-consistent field theory. The leading configuration (96.6%) for the X4ς- ground electronic state was shown to be 1σ2224222111 with an Mg-C bond length of 2.041 Å for a fixed C-H bond length of 1.090 Å. The Mg-C bond dissociation energy (De) was 48.26 kcal/mol. The optimized geometry from a density functional theory calculation using the B3LYP functional gave a Mg-C bond length of 2.061 Å and a C-H bond length of 1.090 Å.

Original languageEnglish
Article number124304
JournalJournal of Chemical Physics
Volume151
Issue number12
DOIs
Publication statusPublished - 28 Sep 2019

Fingerprint

Bond length
Magnesium
Paramagnetic resonance
isolation
Electronic states
magnesium
matrices
carbon 13
Carbon
Metals
Neon
Potential energy surfaces
Acetone
electronics
Electronic structure
Density functional theory
neon
metals
acetone
self consistent fields

Cite this

Hearne, Thomas S. ; Karakyriakos, Emmanuel ; Dunford, Cara L. ; Kettner, Marcus ; Wild, Duncan A. ; McKinley, Allan J. / A matrix isolation ESR investigation of the MgCH radical. In: Journal of Chemical Physics. 2019 ; Vol. 151, No. 12.
@article{da9d96cf404946dea636cb8d2a16d30e,
title = "A matrix isolation ESR investigation of the MgCH radical",
abstract = "The MgCH radical and its magnesium-25, carbon-13, and deuterated isotopologs have been isolated in low temperature neon matrices and examined by the matrix isolation electron spin resonance technique for the first time. The radicals were formed through the reactions of laser ablated natural abundance magnesium metal and magnesium-25 enriched magnesium metal with carbon-13 and deuterated isotopologs of acetone. The MgCH radical was shown to have a X4ς- ground electronic state, and the magnetic parameters determined for this state were g⊥ = 2.001 81(45), g∂ = 2.0018(10), D = 4970(5) MHz, A⊥(13C) = 115(6) MHz, A∂(13C) = 65(15) MHz, A⊥(H) = 34(6) MHz, A∂(H) = 5(10) MHz, A⊥(D) = 5(3) MHz, A⊥(25Mg) = 82(5) MHz, and A∂(25Mg) = 85(10). Comparisons are made between the electronic structure of this radical and the MgCH3 and MgN radicals. Theoretical hyperfine parameters were also evaluated for the MgCH radical, and a potential energy surface for the low-lying electronic states was constructed using complete active space multiconfigurational self-consistent field theory. The leading configuration (96.6{\%}) for the X4ς- ground electronic state was shown to be 1σ22σ23σ21π44σ25σ26σ27σ12π12π1 with an Mg-C bond length of 2.041 {\AA} for a fixed C-H bond length of 1.090 {\AA}. The Mg-C bond dissociation energy (De) was 48.26 kcal/mol. The optimized geometry from a density functional theory calculation using the B3LYP functional gave a Mg-C bond length of 2.061 {\AA} and a C-H bond length of 1.090 {\AA}.",
author = "Hearne, {Thomas S.} and Emmanuel Karakyriakos and Dunford, {Cara L.} and Marcus Kettner and Wild, {Duncan A.} and McKinley, {Allan J.}",
year = "2019",
month = "9",
day = "28",
doi = "10.1063/1.5119146",
language = "English",
volume = "151",
journal = "The Journal of Chemical Physics",
issn = "0021-9606",
publisher = "ACOUSTICAL SOC AMER AMER INST PHYSICS",
number = "12",

}

A matrix isolation ESR investigation of the MgCH radical. / Hearne, Thomas S.; Karakyriakos, Emmanuel; Dunford, Cara L.; Kettner, Marcus; Wild, Duncan A.; McKinley, Allan J.

In: Journal of Chemical Physics, Vol. 151, No. 12, 124304, 28.09.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A matrix isolation ESR investigation of the MgCH radical

AU - Hearne, Thomas S.

AU - Karakyriakos, Emmanuel

AU - Dunford, Cara L.

AU - Kettner, Marcus

AU - Wild, Duncan A.

AU - McKinley, Allan J.

PY - 2019/9/28

Y1 - 2019/9/28

N2 - The MgCH radical and its magnesium-25, carbon-13, and deuterated isotopologs have been isolated in low temperature neon matrices and examined by the matrix isolation electron spin resonance technique for the first time. The radicals were formed through the reactions of laser ablated natural abundance magnesium metal and magnesium-25 enriched magnesium metal with carbon-13 and deuterated isotopologs of acetone. The MgCH radical was shown to have a X4ς- ground electronic state, and the magnetic parameters determined for this state were g⊥ = 2.001 81(45), g∂ = 2.0018(10), D = 4970(5) MHz, A⊥(13C) = 115(6) MHz, A∂(13C) = 65(15) MHz, A⊥(H) = 34(6) MHz, A∂(H) = 5(10) MHz, A⊥(D) = 5(3) MHz, A⊥(25Mg) = 82(5) MHz, and A∂(25Mg) = 85(10). Comparisons are made between the electronic structure of this radical and the MgCH3 and MgN radicals. Theoretical hyperfine parameters were also evaluated for the MgCH radical, and a potential energy surface for the low-lying electronic states was constructed using complete active space multiconfigurational self-consistent field theory. The leading configuration (96.6%) for the X4ς- ground electronic state was shown to be 1σ22σ23σ21π44σ25σ26σ27σ12π12π1 with an Mg-C bond length of 2.041 Å for a fixed C-H bond length of 1.090 Å. The Mg-C bond dissociation energy (De) was 48.26 kcal/mol. The optimized geometry from a density functional theory calculation using the B3LYP functional gave a Mg-C bond length of 2.061 Å and a C-H bond length of 1.090 Å.

AB - The MgCH radical and its magnesium-25, carbon-13, and deuterated isotopologs have been isolated in low temperature neon matrices and examined by the matrix isolation electron spin resonance technique for the first time. The radicals were formed through the reactions of laser ablated natural abundance magnesium metal and magnesium-25 enriched magnesium metal with carbon-13 and deuterated isotopologs of acetone. The MgCH radical was shown to have a X4ς- ground electronic state, and the magnetic parameters determined for this state were g⊥ = 2.001 81(45), g∂ = 2.0018(10), D = 4970(5) MHz, A⊥(13C) = 115(6) MHz, A∂(13C) = 65(15) MHz, A⊥(H) = 34(6) MHz, A∂(H) = 5(10) MHz, A⊥(D) = 5(3) MHz, A⊥(25Mg) = 82(5) MHz, and A∂(25Mg) = 85(10). Comparisons are made between the electronic structure of this radical and the MgCH3 and MgN radicals. Theoretical hyperfine parameters were also evaluated for the MgCH radical, and a potential energy surface for the low-lying electronic states was constructed using complete active space multiconfigurational self-consistent field theory. The leading configuration (96.6%) for the X4ς- ground electronic state was shown to be 1σ22σ23σ21π44σ25σ26σ27σ12π12π1 with an Mg-C bond length of 2.041 Å for a fixed C-H bond length of 1.090 Å. The Mg-C bond dissociation energy (De) was 48.26 kcal/mol. The optimized geometry from a density functional theory calculation using the B3LYP functional gave a Mg-C bond length of 2.061 Å and a C-H bond length of 1.090 Å.

UR - http://www.scopus.com/inward/record.url?scp=85072756795&partnerID=8YFLogxK

U2 - 10.1063/1.5119146

DO - 10.1063/1.5119146

M3 - Article

VL - 151

JO - The Journal of Chemical Physics

JF - The Journal of Chemical Physics

SN - 0021-9606

IS - 12

M1 - 124304

ER -