東華大學圖書館 |

High-Velocity Impact Dissociation of Molecular Species in Spacecraft-Based Mass Spectrometers.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	High-Velocity Impact Dissociation of Molecular Species in Spacecraft-Based Mass Spectrometers./
作者:	Turner, Brandon M.
面頁冊數:	1 online resource (112 pages)
附註:	Source: Dissertations Abstracts International, Volume: 84-05, Section: B.
Contained By:	Dissertations Abstracts International84-05B.
標題:	Aeronautics. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29730566click for full text (PQDT)
ISBN:	9798352976951

High-Velocity Impact Dissociation of Molecular Species in Spacecraft-Based Mass Spectrometers.
Turner, Brandon M.

High-Velocity Impact Dissociation of Molecular Species in Spacecraft-Based Mass Spectrometers. - 1 online resource (112 pages)

Source: Dissertations Abstracts International, Volume: 84-05, Section: B.

Thesis (Ph.D.)--Brigham Young University, 2022.

Includes bibliographical references

Mass spectrometers have proven to be vital to understanding the Solar System and the planets within it. Spacecraft containing mass spectrometers have been sent to numerous remote places and have determined important information about the atmospheric composition of Venus, Earth, Mars, Jupiter, and Saturn, along with other celestial bodies. Such results have shown a variety of small neutral molecules, such as CH4 NH3, H2O, CO2, and CO, neutral radicals such as atomic O, H, and N, and a host of small ions, such as H+, N+, and NH4+. Closed ion source inlets, which allow for the detection of these small neutral molecules, contain a spherical antechamber that allows the neutrals to thermalize with the walls of the chamber through many successive collisions before they are introduced into the ionization region of the spacecraft mass spectrometer. These collisions, however, energetically excite neutral molecules and lead to many chemical changes, such as racemization, ionization, or even dissociation. When these changes occur, smaller neutrals can be produced, even if they were not in the original sample from the atmosphere or surface. As a result, the determination of the true composition of an atmosphere or a surface is cast into doubt.Herein is given a brief description of mass spectrometry in space research and how the closed ion source has greatly assisted this process. Dissociation and other chemical changes caused by the high velocity impacts that occur in closed source antechambers is also addressed. A theoretical approach to understanding such dissociative processes that occur after high energy collisions in closed source antechambers is described and undertaken. Chapter 2 describes a proof-of-concept study using hexane as a representative molecule and determines the velocity at which widespread dissociation of hexane molecules is likely to occur in closed source antechambers. This same theoretical process is then utilized in Chapter 3 with many more members of the n-alkane family to probe what effect molecular weight has on the amount of dissociation. Alkanes of both higher and lower molecular weight than hexane (C6H14) are used to show the effect as a function of molecular weight. In all cases, it was found that the velocity at which half of the incoming neutral n-alkane molecules dissociate is roughly the same for all molecular weights studied. This result is then applied to current and future space research through a proposed hardware solution, which will reduce the amount of dissociation and a discussion of how this effect may be seen in the results obtained from future mission instruments. Lastly, future work with different molecular weights and with successive collisions (the second, third, fourth, etc.) is described. This future work will further expand the present study to show how different functional groups, which may be partly responsible for higher-than-expected levels of NH3 and CO2, are affected after a high velocity, high energy impact.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798352976951Subjects--Topical Terms:

560293
Aeronautics.
Index Terms--Genre/Form:

542853
Electronic books.

High-Velocity Impact Dissociation of Molecular Species in Spacecraft-Based Mass Spectrometers.
LDR:04343nmm a2200385K 4500 001 2359578
005 20230917195750.5
006 m o d
007 cr mn ---uuuuu
008 241011s2022 xx obm 000 0 eng d
020 $a 9798352976951
035 $a (MiAaPQ)AAI29730566
035 $a (MiAaPQ)BrighamYoung10681
035 $a AAI29730566
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Turner, Brandon M. $3 3382086
245 1 0 $a High-Velocity Impact Dissociation of Molecular Species in Spacecraft-Based Mass Spectrometers.
264 0 $c 2022
300 $a 1 online resource (112 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 84-05, Section: B.
500 $a Advisor: Austin, Daniel E.
502 $a Thesis (Ph.D.)--Brigham Young University, 2022.
504 $a Includes bibliographical references
520 $a Mass spectrometers have proven to be vital to understanding the Solar System and the planets within it. Spacecraft containing mass spectrometers have been sent to numerous remote places and have determined important information about the atmospheric composition of Venus, Earth, Mars, Jupiter, and Saturn, along with other celestial bodies. Such results have shown a variety of small neutral molecules, such as CH4 NH3, H2O, CO2, and CO, neutral radicals such as atomic O, H, and N, and a host of small ions, such as H+, N+, and NH4+. Closed ion source inlets, which allow for the detection of these small neutral molecules, contain a spherical antechamber that allows the neutrals to thermalize with the walls of the chamber through many successive collisions before they are introduced into the ionization region of the spacecraft mass spectrometer. These collisions, however, energetically excite neutral molecules and lead to many chemical changes, such as racemization, ionization, or even dissociation. When these changes occur, smaller neutrals can be produced, even if they were not in the original sample from the atmosphere or surface. As a result, the determination of the true composition of an atmosphere or a surface is cast into doubt.Herein is given a brief description of mass spectrometry in space research and how the closed ion source has greatly assisted this process. Dissociation and other chemical changes caused by the high velocity impacts that occur in closed source antechambers is also addressed. A theoretical approach to understanding such dissociative processes that occur after high energy collisions in closed source antechambers is described and undertaken. Chapter 2 describes a proof-of-concept study using hexane as a representative molecule and determines the velocity at which widespread dissociation of hexane molecules is likely to occur in closed source antechambers. This same theoretical process is then utilized in Chapter 3 with many more members of the n-alkane family to probe what effect molecular weight has on the amount of dissociation. Alkanes of both higher and lower molecular weight than hexane (C6H14) are used to show the effect as a function of molecular weight. In all cases, it was found that the velocity at which half of the incoming neutral n-alkane molecules dissociate is roughly the same for all molecular weights studied. This result is then applied to current and future space research through a proposed hardware solution, which will reduce the amount of dissociation and a discussion of how this effect may be seen in the results obtained from future mission instruments. Lastly, future work with different molecular weights and with successive collisions (the second, third, fourth, etc.) is described. This future work will further expand the present study to show how different functional groups, which may be partly responsible for higher-than-expected levels of NH3 and CO2, are affected after a high velocity, high energy impact.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Aeronautics. $3 560293
650 4 $a Mass spectrometry. $3 551172
650 4 $a Space exploration. $3 3696172
650 4 $a Solar system. $3 520348
650 4 $a Gold. $3 659820
650 4 $a Gases. $3 559387
650 4 $a Surface chemistry. $3 551428
650 4 $a Atmosphere. $3 542821
650 4 $a Titanium. $3 3315393
650 4 $a Orbits. $3 534192
650 4 $a Altitude. $3 746362
650 4 $a Planetary systems. $3 3526183
650 4 $a Carbon dioxide. $3 587886
650 4 $a Design. $3 518875
650 4 $a Molecular weight. $3 3683783
650 4 $a Scientific imaging. $3 3560377
650 4 $a Energy. $3 876794
650 4 $a Saturn. $3 3700188
650 4 $a Aerospace engineering. $3 1002622
650 4 $a Analytical chemistry. $3 3168300
650 4 $a Astronomy. $3 517668
650 4 $a Chemistry. $3 516420
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0791
690 $a 0389
690 $a 0538
690 $a 0486
690 $a 0606
690 $a 0485
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a Brigham Young University. $3 1017451
773 0 $t Dissertations Abstracts International $g 84-05B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29730566 $z click for full text (PQDT)