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Measurement of the orientation of buffer-gas-cooled, electrostatically-guided ammonia molecules

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Measurement of the orientation of buffer-gas-cooled, electrostatically-guided ammonia molecules. / Steer, Edward W.; Petralia, Lorenzo S.; Western, Colin M.; Heazlewood, Brianna R.; Softley, Timothy P.

In: Journal of Molecular Spectroscopy, Vol. 332, 02.2017, p. 94-102.

Research output: Contribution to journalArticle

Harvard

Steer, EW, Petralia, LS, Western, CM, Heazlewood, BR & Softley, TP 2017, 'Measurement of the orientation of buffer-gas-cooled, electrostatically-guided ammonia molecules', Journal of Molecular Spectroscopy, vol. 332, pp. 94-102. https://doi.org/10.1016/j.jms.2016.11.003

APA

Steer, E. W., Petralia, L. S., Western, C. M., Heazlewood, B. R., & Softley, T. P. (2017). Measurement of the orientation of buffer-gas-cooled, electrostatically-guided ammonia molecules. Journal of Molecular Spectroscopy, 332, 94-102. https://doi.org/10.1016/j.jms.2016.11.003

Vancouver

Steer EW, Petralia LS, Western CM, Heazlewood BR, Softley TP. Measurement of the orientation of buffer-gas-cooled, electrostatically-guided ammonia molecules. Journal of Molecular Spectroscopy. 2017 Feb;332:94-102. https://doi.org/10.1016/j.jms.2016.11.003

Author

Steer, Edward W. ; Petralia, Lorenzo S. ; Western, Colin M. ; Heazlewood, Brianna R. ; Softley, Timothy P. / Measurement of the orientation of buffer-gas-cooled, electrostatically-guided ammonia molecules. In: Journal of Molecular Spectroscopy. 2017 ; Vol. 332. pp. 94-102.

Bibtex

@article{61e8948217b34d68a1f25d241db8bec4,
title = "Measurement of the orientation of buffer-gas-cooled, electrostatically-guided ammonia molecules",
abstract = "The extent to which the spatial orientation of internally and translationally cold ammonia molecules can be controlled as molecules pass out of a quadrupole guide and through different electric field regions is examined. Ammonia molecules are collisionally cooled in a buffer gas cell, and are subsequently guided by a three-bend electrostatic quadrupole into a detection chamber. The orientation of ammonia molecules is probed using (2+1) resonance-enhanced multiphoton ionisation (REMPI), with the laser polarisation axis aligned both parallel and perpendicular to the time-of-flight axis. Even with the presence of a near-zero field region, the ammonia REMPI spectra indicate some retention of orientation. Monte Carlo simulations propagating the time-dependent Schr{\"o}dinger equation in a full basis set including the hyperfine interaction enable the orientation of ammonia molecules to be calculated – with respect to both the local field direction and a space-fixed axis – as the molecules pass through different electric field regions. The simulations indicate that the orientation of ∼ 95{\%} of ammonia molecules in J K = 1 1 could be achieved with the application of a small bias voltage (17 V) to the mesh separating the quadrupole and detection regions. Following the recent combination of the buffer gas cell and quadrupole guide apparatus with a linear Paul ion trap, this result could enable one to examine the influence of molecular orientation on ion-molecule reaction dynamics and kinetics.",
keywords = "Cold molecules, Quadrupole guide, Alignment, Ammonia, Polarisation",
author = "Steer, {Edward W.} and Petralia, {Lorenzo S.} and Western, {Colin M.} and Heazlewood, {Brianna R.} and Softley, {Timothy P.}",
year = "2017",
month = "2",
doi = "10.1016/j.jms.2016.11.003",
language = "English",
volume = "332",
pages = "94--102",
journal = "Journal of Molecular Spectroscopy",
issn = "0022-2852",
publisher = "Elsevier Inc.",

}

RIS - suitable for import to EndNote

TY - JOUR

T1 - Measurement of the orientation of buffer-gas-cooled, electrostatically-guided ammonia molecules

AU - Steer, Edward W.

AU - Petralia, Lorenzo S.

AU - Western, Colin M.

AU - Heazlewood, Brianna R.

AU - Softley, Timothy P.

PY - 2017/2

Y1 - 2017/2

N2 - The extent to which the spatial orientation of internally and translationally cold ammonia molecules can be controlled as molecules pass out of a quadrupole guide and through different electric field regions is examined. Ammonia molecules are collisionally cooled in a buffer gas cell, and are subsequently guided by a three-bend electrostatic quadrupole into a detection chamber. The orientation of ammonia molecules is probed using (2+1) resonance-enhanced multiphoton ionisation (REMPI), with the laser polarisation axis aligned both parallel and perpendicular to the time-of-flight axis. Even with the presence of a near-zero field region, the ammonia REMPI spectra indicate some retention of orientation. Monte Carlo simulations propagating the time-dependent Schrödinger equation in a full basis set including the hyperfine interaction enable the orientation of ammonia molecules to be calculated – with respect to both the local field direction and a space-fixed axis – as the molecules pass through different electric field regions. The simulations indicate that the orientation of ∼ 95% of ammonia molecules in J K = 1 1 could be achieved with the application of a small bias voltage (17 V) to the mesh separating the quadrupole and detection regions. Following the recent combination of the buffer gas cell and quadrupole guide apparatus with a linear Paul ion trap, this result could enable one to examine the influence of molecular orientation on ion-molecule reaction dynamics and kinetics.

AB - The extent to which the spatial orientation of internally and translationally cold ammonia molecules can be controlled as molecules pass out of a quadrupole guide and through different electric field regions is examined. Ammonia molecules are collisionally cooled in a buffer gas cell, and are subsequently guided by a three-bend electrostatic quadrupole into a detection chamber. The orientation of ammonia molecules is probed using (2+1) resonance-enhanced multiphoton ionisation (REMPI), with the laser polarisation axis aligned both parallel and perpendicular to the time-of-flight axis. Even with the presence of a near-zero field region, the ammonia REMPI spectra indicate some retention of orientation. Monte Carlo simulations propagating the time-dependent Schrödinger equation in a full basis set including the hyperfine interaction enable the orientation of ammonia molecules to be calculated – with respect to both the local field direction and a space-fixed axis – as the molecules pass through different electric field regions. The simulations indicate that the orientation of ∼ 95% of ammonia molecules in J K = 1 1 could be achieved with the application of a small bias voltage (17 V) to the mesh separating the quadrupole and detection regions. Following the recent combination of the buffer gas cell and quadrupole guide apparatus with a linear Paul ion trap, this result could enable one to examine the influence of molecular orientation on ion-molecule reaction dynamics and kinetics.

KW - Cold molecules

KW - Quadrupole guide

KW - Alignment

KW - Ammonia

KW - Polarisation

U2 - 10.1016/j.jms.2016.11.003

DO - 10.1016/j.jms.2016.11.003

M3 - Article

VL - 332

SP - 94

EP - 102

JO - Journal of Molecular Spectroscopy

JF - Journal of Molecular Spectroscopy

SN - 0022-2852

ER -