<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Eszter Sendula</dc:contributor>
  <dc:contributor>Hector Lamadrid</dc:contributor>
  <dc:contributor>Matthew Steele-MacInnis</dc:contributor>
  <dc:contributor>Georg Spiekermann</dc:contributor>
  <dc:contributor>Robert Burruss</dc:contributor>
  <dc:contributor>Robert J. Bodnar</dc:contributor>
  <dc:creator>D. Matthew Sublett</dc:creator>
  <dc:date>2020</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The Raman spectra of pure N&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, and CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;were analyzed over the range 10 to 500 bars and from −160°C to 200°C (N&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;), 22°C to 350°C (CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;), and −100°C to 450°C (CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;). At constant temperature, Raman peak position, including the more intense CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;peak (&lt;/span&gt;&lt;i&gt;ν&lt;/i&gt;&lt;span&gt;+), decreases (shifts to lower wave number) with increasing pressure for all three gases over the entire pressure and temperature (&lt;/span&gt;&lt;i&gt;PT&lt;/i&gt;&lt;span&gt;) range studied. At constant pressure, the peak position for CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;increases (shifts to higher wave number) with increasing temperature over the entire&amp;nbsp;&lt;/span&gt;&lt;i&gt;PT&lt;/i&gt;&lt;span&gt;&amp;nbsp;range studied. In contrast, N&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;first shows an increase in peak position with increasing temperature at constant pressure, followed by a decrease in peak position with increasing temperature. The inflection temperature at which the trend reverses for N&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;is located between 0°C and 50°C at pressures above ~50 bars and is pressure dependent. Below ~50 bars, the inflection temperature was observed as low as −120°C. The shifts in Raman peak positions with&amp;nbsp;&lt;/span&gt;&lt;i&gt;PT&lt;/i&gt;&lt;span&gt;&amp;nbsp;are related to relative density changes, which reflect changes in intermolecular attraction and repulsion. A conceptual model relating the Raman spectral properties of N&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, and CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;to relative density (volume) changes and attractive and repulsive forces is presented here. Additionally, reduced temperature-dependent densimeters and barometers are presented for each pure component over the respective&amp;nbsp;&lt;/span&gt;&lt;i&gt;PT&lt;/i&gt;&lt;span&gt;&amp;nbsp;ranges. The Raman spectral behavior of the pure gases as a function of temperature and pressure is assessed to provide a framework for understanding the behavior of each component in multicomponent N&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;-CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;-CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;gas systems in a future study.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1002/jrs.5805</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Wiley</dc:publisher>
  <dc:title>Shift in the Raman symmetric stretching band of N2, CO2, and CH4 as a function of temperature, pressure, and density</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>