Quadrupole coupling in alkali metal amides MNH2 (X~1A1): An experimental and computational study

M. A. Burton, B. T. Russ, M. P. Bucchino, P. M. Sheridan, L. M. Ziurys

Research output: Contribution to journalArticle

Abstract

Rotational spectra of LiNH2 and NaNH2 have been recorded using Fourier transform microwave/millimeter-wave (FTMmmW) techniques in the range 22 – 59 GHz. The species were created from the reaction of metal vapor and ammonia, diluted in argon, using a Discharge-Assisted Laser Ablation Source (DALAS). The JKa,Kc = 101 → 000 transition was measured for both molecules, as well as the JKa,Kc = 202 → 101 transition for NaNH2, all of which exhibited quadrupole coupling splittings. The two data sets were each analyzed with an S-reduced asymmetric top Hamiltonian, establishing the lithium and sodium electric quadrupole coupling parameter, χaa for the first time, and refining previous rotational constants. Quadrupole and nuclear-spin rotation interactions were also computationally investigated at the MP2/6-311G++(3df,2pd) level for LiNH2, NaNH2 and KNH2. These calculations suggest that the major contributor to the quadrupole interactions is the alkali metal nucleus, not that of nitrogen, as confirmed experimentally. Comparison of quadrupole coupling constants suggest that LiNH2 and NaNH2 are principally ionic molecules with a charge distribution similar to LiF and NaF.

Original languageEnglish (US)
Article number111211
JournalJournal of Molecular Spectroscopy
Volume365
DOIs
StatePublished - Nov 2019

Fingerprint

Alkali Metals
Amides
alkali metals
amides
quadrupoles
Hamiltonians
Molecules
Argon
Charge distribution
Laser ablation
Lithium
Ammonia
Millimeter waves
Refining
Fourier transforms
Nitrogen
Metals
Sodium
Vapors
Microwaves

Keywords

  • Fourier transform microwave spectroscopy
  • Laser ablation
  • Metal amides
  • Quadrupole coupling

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Spectroscopy
  • Physical and Theoretical Chemistry

Cite this

Quadrupole coupling in alkali metal amides MNH2 (X~1A1) : An experimental and computational study. / Burton, M. A.; Russ, B. T.; Bucchino, M. P.; Sheridan, P. M.; Ziurys, L. M.

In: Journal of Molecular Spectroscopy, Vol. 365, 111211, 11.2019.

Research output: Contribution to journalArticle

@article{173d39082a194aeab8d12d6fa1b11fe6,
title = "Quadrupole coupling in alkali metal amides MNH2 (X~1A1): An experimental and computational study",
abstract = "Rotational spectra of LiNH2 and NaNH2 have been recorded using Fourier transform microwave/millimeter-wave (FTMmmW) techniques in the range 22 – 59 GHz. The species were created from the reaction of metal vapor and ammonia, diluted in argon, using a Discharge-Assisted Laser Ablation Source (DALAS). The JKa,Kc = 101 → 000 transition was measured for both molecules, as well as the JKa,Kc = 202 → 101 transition for NaNH2, all of which exhibited quadrupole coupling splittings. The two data sets were each analyzed with an S-reduced asymmetric top Hamiltonian, establishing the lithium and sodium electric quadrupole coupling parameter, χaa for the first time, and refining previous rotational constants. Quadrupole and nuclear-spin rotation interactions were also computationally investigated at the MP2/6-311G++(3df,2pd) level for LiNH2, NaNH2 and KNH2. These calculations suggest that the major contributor to the quadrupole interactions is the alkali metal nucleus, not that of nitrogen, as confirmed experimentally. Comparison of quadrupole coupling constants suggest that LiNH2 and NaNH2 are principally ionic molecules with a charge distribution similar to LiF and NaF.",
keywords = "Fourier transform microwave spectroscopy, Laser ablation, Metal amides, Quadrupole coupling",
author = "Burton, {M. A.} and Russ, {B. T.} and Bucchino, {M. P.} and Sheridan, {P. M.} and Ziurys, {L. M.}",
year = "2019",
month = "11",
doi = "10.1016/j.jms.2019.111211",
language = "English (US)",
volume = "365",
journal = "Journal of Molecular Spectroscopy",
issn = "0022-2852",
publisher = "Academic Press Inc.",

}

TY - JOUR

T1 - Quadrupole coupling in alkali metal amides MNH2 (X~1A1)

T2 - An experimental and computational study

AU - Burton, M. A.

AU - Russ, B. T.

AU - Bucchino, M. P.

AU - Sheridan, P. M.

AU - Ziurys, L. M.

PY - 2019/11

Y1 - 2019/11

N2 - Rotational spectra of LiNH2 and NaNH2 have been recorded using Fourier transform microwave/millimeter-wave (FTMmmW) techniques in the range 22 – 59 GHz. The species were created from the reaction of metal vapor and ammonia, diluted in argon, using a Discharge-Assisted Laser Ablation Source (DALAS). The JKa,Kc = 101 → 000 transition was measured for both molecules, as well as the JKa,Kc = 202 → 101 transition for NaNH2, all of which exhibited quadrupole coupling splittings. The two data sets were each analyzed with an S-reduced asymmetric top Hamiltonian, establishing the lithium and sodium electric quadrupole coupling parameter, χaa for the first time, and refining previous rotational constants. Quadrupole and nuclear-spin rotation interactions were also computationally investigated at the MP2/6-311G++(3df,2pd) level for LiNH2, NaNH2 and KNH2. These calculations suggest that the major contributor to the quadrupole interactions is the alkali metal nucleus, not that of nitrogen, as confirmed experimentally. Comparison of quadrupole coupling constants suggest that LiNH2 and NaNH2 are principally ionic molecules with a charge distribution similar to LiF and NaF.

AB - Rotational spectra of LiNH2 and NaNH2 have been recorded using Fourier transform microwave/millimeter-wave (FTMmmW) techniques in the range 22 – 59 GHz. The species were created from the reaction of metal vapor and ammonia, diluted in argon, using a Discharge-Assisted Laser Ablation Source (DALAS). The JKa,Kc = 101 → 000 transition was measured for both molecules, as well as the JKa,Kc = 202 → 101 transition for NaNH2, all of which exhibited quadrupole coupling splittings. The two data sets were each analyzed with an S-reduced asymmetric top Hamiltonian, establishing the lithium and sodium electric quadrupole coupling parameter, χaa for the first time, and refining previous rotational constants. Quadrupole and nuclear-spin rotation interactions were also computationally investigated at the MP2/6-311G++(3df,2pd) level for LiNH2, NaNH2 and KNH2. These calculations suggest that the major contributor to the quadrupole interactions is the alkali metal nucleus, not that of nitrogen, as confirmed experimentally. Comparison of quadrupole coupling constants suggest that LiNH2 and NaNH2 are principally ionic molecules with a charge distribution similar to LiF and NaF.

KW - Fourier transform microwave spectroscopy

KW - Laser ablation

KW - Metal amides

KW - Quadrupole coupling

UR - http://www.scopus.com/inward/record.url?scp=85073208114&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85073208114&partnerID=8YFLogxK

U2 - 10.1016/j.jms.2019.111211

DO - 10.1016/j.jms.2019.111211

M3 - Article

AN - SCOPUS:85073208114

VL - 365

JO - Journal of Molecular Spectroscopy

JF - Journal of Molecular Spectroscopy

SN - 0022-2852

M1 - 111211

ER -