Cover Page The handle

Cover Page

The handle http://hdl.handle.net/1887/41186 holds various files of this Leiden University dissertation.

Author: Paardekooper, D.M.

Title: Shining light on interstellar matter : a laboratory study

Issue Date: 2016-07-05

Shining Light on Interstellar Matter A laboratory study

Daniel Paardekooper

Daniel Paardekooper 2016 c

Niets uit deze uitgave mag worden verveelvoudigd, opgeslagen in een geautomatiseerd gegevensbestand of openbaar gemaakt worden in enige vorm of op enige wijze zonder voorafgaande schriftelijke toestemming van de auteur.

Shining Light on Interstellar Matter, A laboratory study, Thesis, Leiden University.

130 pages; illustrated, with bibliographic references and summary in Dutch.

isbn/ean: 978-94-028-0233-7 Printed by Ipskamp Drukkers.

Cover design by Daan Boltje, image of The Horsehead Nebula from José Jimenez Priego.

This work has been financially supported by the Nederlandse Organisatie voor Wetenschap-

pelijk Onderzoek.

Shining Light on Interstellar Matter A laboratory study

Proefschrift

ter verkrijging van

de graad van doctor aan de Universiteit Leiden

op gezag van de Rector Magnificus prof. mr. C. J. J. M. Stolker, volgens besluit van het College voor Promoties

te verdedigen op dinsdag 5 Juli 2016 klokke 16.15 uur

door

Daniël Mathijs Paardekooper

geboren te Schiedam

in 1986

Promotiecommissie

Promotor Prof. dr. H. V. J. Linnartz Overige leden Prof. dr. H. J. A. Röttgering

Prof. dr. A. G. G. M. Tielens

Prof. dr. W. A. Brown Sussex University

Dr. M. S. Gudipati NASA’s Jet Propulsion Laboratory

Dr. S. Ioppolo The Open University, Milton Keynes

C O N T E N T S

1 i n t r o d u c t i o n 1 1 .1 Ice composition 2

1 .2 Ice evolution through different stages of star formation 3 1 .3 Laboratory astrochemistry 5

1 .4 This thesis 8

2 l a s e r d e s o r p t i o n t i m e -of-flight mass spectrometry of vuv photo- p r o c e s s e d i c e s 11

2 .1 Introduction 12 2 .2 System description 13

2 .2.1 Main chamber 14 2 .2.2 Flight tube 15 2 .2.3 Analytical tools 16 2 .2.4 Calibration experiments 17 2 .2.5 Experimental Concept 18 2 .3 Results 19

2 .3.1 Kinetic study: qualitative approach 20 2 .3.2 Kinetic study: quantitative approach 21 2 .3.3 Validation experiments 24

2 .4 Conclusions 27

3 c o n t r o l l i n g t h e e m i s s i o n p r o f i l e o f a m i c r o wav e d r i v e n h

d i s c h a r g e l a m p t o s i m u l at e i n t e r s t e l l a r r a d i at i o n f i e l d s 31 3 .1 Introduction 32

3 .2 Experimental 33

3 .2.1 Microwave discharge hydrogen-flow lamp 33 3 .2.2 Greifswald UV/VUV spectrometer 34 3 .2.3 Photon flux measurements 35 3 .2.4 CryoPAD II 36

3 .3 Results 37

3 .3.1 Photon flux 37

3 .3.2 H

pressure dependence 37 3 .3.3 Mixtures and different gasses 38 3 .3.4 MDHL power dependence 40

3 .3.5 Pumping efficiency in F- and T-type MDHLs 41 3 .3.6 Distance dependence 42

3 .3.7 Practical issues 44

3 .3.8 CO photodepletion measurements 45 3 .4 Conclusions 47

4 m e t h a n e i c e p h o t o c h e m i s t r y a n d k i n e t i c s t u d y u s i n g l a s e r d e s o r p t i o n t i m e -of-flight mass spectrometry at 20 k 49 4 .1 Introduction 50

4 .2 Experimental approach 51

4 .3 Results 52

4 .3.1 Proposed reaction scheme 55

4 .3.2 Fitting procedure and data treatment 57 4 .4 Discussion 59

4 .5 Conclusions 62

5 l a s e r d e s o r p t i o n t i m e -of-flight mass spectrometry of vuv photo- p r o c e s s e d m e t h a n o l i c e 65

5 .1 Introduction 66

5 .2 Experiments and analysis 68 5 .2.1 Experiments 68 5 .2.2 Analysis 69 5 .3 Experimental results 71

5 .3.1 Qualitative analysis 72 5 .3.2 Quantitative analysis 76 5 .4 Discussion 86

5 .4.1 Comparison with previous experiments 86 5 .4.2 CH

OH photo-dissocation branching ratio 88 5 .4.3 Glycerin formation mechanism 89

5 .5 Astrophysical implications and conclusions 89

6 a n ov e l a p p r oa c h t o m e a s u r e p h o t o d e s o r p t i o n r at e s o f i n t e r - s t e l l a r i c e a na l o g u e s 93

6 .1 Introduction 94

6 .2 Experimental Methods 95 6 .2.1 Experimental setup 95 6 .2.2 Deposition rate calibration 96 6 .2.3 Photon flux calibration 97 6 .2.4 Detection scheme 97 6 .3 Results 99

6 .3.1 Plume characterisation of laser desorbed CO ice 99 6 .3.2 Photodesorption of CO ice at 20 K 100

6 .4 Discussion and astrophysical implications 101 6 .4.1 Overview of the CO photodesorption rates 101 6 .4.2 Astrophysical implications 103

6 .5 Conclusion 103

7 q ua d r u p o l e i o n t r a p /time-of-flight photo-fragmentation

s p e c t r o m e t r y o f t h e h e x a -peri-hexabenzocoronene (hbc) cation 107 7 .1 Introduction 108

7 .2 Experiment 108

7 .3 Results and discussion 110 7 .4 Astrophysical relevance 115 7 .5 Conclusion 116

s a m e n vat t i n g 119

l i s t o f p u b l i c at i o n s 125

a b o u t t h e au t h o r 127

a c k n o w l e d g e m e n t 129