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Search Publications by: Joseph T. Hodges (Fed)

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Displaying 1 - 25 of 106

The 3-0 Quadrupole Band in H2 by Cavity Ring-Down Spectroscopy

October 12, 2021
Author(s)
D C. Robie, Joseph T. Hodges
Several lines in the S and Q branches (including the previously unobserved Q32 and Q33 lines) of the 3-0 quadrupole band of H2 have been detected by cavity ring-down spectroscopy using a multimode laser with a long cavity. The noise equivalent absorption

Pilot Comparison CCQM-P177 - Monoterpenes in Nitrogen at 2.5 nmol mol-1 Final Report

September 27, 2021
Author(s)
Christina Cecelski, George C. Rhoderick, Joseph T. Hodges, Antonio Possolo, Olaf Wilke
The growing awareness of climate change, and continuing concerns regarding tropospheric and stratospheric chemistry, will require future measurements and standards for compounds linked to these issues. To globally monitor and control the emissions of these

Improvement of the spectroscopic parameters of the air- and self-broadened N2O and CO lines for the HITRAN2020 database applications

June 11, 2021
Author(s)
Robab Hashemi, Iouli Gordon, Erin Adkins, Joseph T. Hodges, Manfred Birk, David Long, Chris Boone, Adam Fleisher, Adriana Predoi-Cross, Laurence Rothman
This paper outlines the major update of the line-shape parameters that were performed for the nitrous oxide (N2O) and carbon monoxide (CO) molecules listed in the HITRAN2020 database. We reviewed the collected measurements for the air- and self-broadened

Comparison of primary laser spectroscopy and mass spectrometry methods for measuring mass concentration of gaseous elemental mercury

December 10, 2020
Author(s)
Abneesh Srivastava, Stephen E. Long, James E. Norris, Colleen E. Bryan Sallee, Jennifer Carney, Joseph Hodges
We present a direct comparison between two independent methods for the measurement of gaseous elemental mercury (GEM) mass concentration: isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICP-MS) and laser absorption

Improving the Retrieval of XCO2 from Total Carbon Column Network Solar Spectra

January 3, 2019
Author(s)
Joseph Mendonca, Kimberly Strong, Debra Wunch, Geoffrey Toon, David Long, Joseph T. Hodges, Vincent T. Sironneau
High-resolution absorption spectra of the a^1 ∆_g←X^3 Σ_g^- O2 band measured using cavity ring-down spectroscopy were fitted using the Voigt and speed-dependent Voigt line shapes. We found that the speed-dependent Voigt line shape was better able to model

CCQM K121 – Monoterpenes in Nitrogen at 2.5 nmol mol-1 Final Report

November 9, 2018
Author(s)
Christina E. Cecelski, George C. Rhoderick, Joseph T. Hodges, Antonio M. Possolo, Cassie A. Goodman, Yong D. Kim, Dal H. Kim, Sangil Lee, Nicholas Allen, Marivon Corbel, David Worton, Richard Brown, Paul Brewer
The growing awareness of climate change, and continuing concerns regarding tropospheric and stratospheric chemistry, will require future measurements and standards for compounds linked to these issues. To monitor and control the emissions of these species

NIST Standards for Measurement, Instrument Calibration, and Quantification of Gaseous Atmospheric Species

March 2, 2018
Author(s)
George C. Rhoderick, Michael E. Kelley, Walter R. Miller Jr., James E. Norris, Jennifer Carney, Lyn Gameson, Christina Cecelski, Cassie Goodman, Abneesh Srivastava, Joseph Hodges
There are many gas species present in the atmosphere that are associated with the earth’s climate. These compounds absorb and emit radiation, a process which is the fundamental cause of the greenhouse effect. The major greenhouse gases in the earth’s

Multiheterodyne Spectroscopy Using Multi-frequency Combs

May 13, 2017
Author(s)
David F. Plusquellic, Gerd A. Wagner, Adam Fleisher, David Long, Joseph T. Hodges
Near-IR dual frequency combs generated from waveform driven electro-optic phase modulators (EOMs) are used for high resolution studies in low pressure cells and for remote sensing from natural targets (Boulder Flatirons). Arbitrary waveform generators

Multiplexed sub-Doppler spectroscopy with an optical frequency comb

December 13, 2016
Author(s)
David A. Long, Adam J. Fleisher, David F. Plusquellic, Joseph T. Hodges
An optical frequency comb generated with an electro-optic phase modulator and a chirped radiofrequency waveform is used to perform saturation spectroscopy on the D1 and D2 transitions of atomic potassium. With a comb tooth spacing of 2 MHz and a bandwidth