Synchrotron radiation studies of gas phase molecules; from hydrogen to DNA sugars
Författare
Summary, in English
This thesis summarises experimental results on the molecular spectroscopy
of gas phase molecules excited by synchrotron radiation in the VUV and soft
X-ray regions. We have used three different detection techniques, photon in-
duced fluorescence spectroscopy, photoionisation mass spectroscopy and near
edge X-ray absorption fine structure spectroscopy to study molecular deu-
terium, hydrogen sulphide, ammonia, methanol, pyridine, pyridazine, pyrim-
idine, pyrazine, s-triazine, and 2-deoxy-D-ribose, the last one also known as
the DNA sugar. Out of this variety of techniques and molecules we have
shown that: (1) high resolution dispersed fluorescence allows us to identify
vibrational and rotational bands in molecular deuterium, as well as to esti-
mate the predissociation probability of the same molecule [paper I]; (2) the
main species fluorescing after core excitation of methane, ammonia [paper
III], hydrogen sulphide [paper II], pyridine, pyrimidine and s-triazine is H
Balmer α, followed by fluorescence from ionised species, molecular bands and
Balmer β, γ , δ; (3) the Rydberg enhancement seen in fluorescence measure-
ments of water [Melero et al. PRL 96 (2006) 063003], corroborated later in
H2 S [paper II], N H3 [paper III] and C H4 [paper III] and postulated as gen-
eral behaviour for molecules formed by low-Z atoms, is also seen in larger
organic cyclic molecules, e.g. azabenzenes; (4) when dissociative ionisation
of pyridine, pyridazine, pyrimidine, pyrazine, s-triazine and 2-deoxy-D-ribose
occurs, concerted bond rearrangement and nuclear motion takes place as op-
posed to stepwise dissociation [papers V and VI].
of gas phase molecules excited by synchrotron radiation in the VUV and soft
X-ray regions. We have used three different detection techniques, photon in-
duced fluorescence spectroscopy, photoionisation mass spectroscopy and near
edge X-ray absorption fine structure spectroscopy to study molecular deu-
terium, hydrogen sulphide, ammonia, methanol, pyridine, pyridazine, pyrim-
idine, pyrazine, s-triazine, and 2-deoxy-D-ribose, the last one also known as
the DNA sugar. Out of this variety of techniques and molecules we have
shown that: (1) high resolution dispersed fluorescence allows us to identify
vibrational and rotational bands in molecular deuterium, as well as to esti-
mate the predissociation probability of the same molecule [paper I]; (2) the
main species fluorescing after core excitation of methane, ammonia [paper
III], hydrogen sulphide [paper II], pyridine, pyrimidine and s-triazine is H
Balmer α, followed by fluorescence from ionised species, molecular bands and
Balmer β, γ , δ; (3) the Rydberg enhancement seen in fluorescence measure-
ments of water [Melero et al. PRL 96 (2006) 063003], corroborated later in
H2 S [paper II], N H3 [paper III] and C H4 [paper III] and postulated as gen-
eral behaviour for molecules formed by low-Z atoms, is also seen in larger
organic cyclic molecules, e.g. azabenzenes; (4) when dissociative ionisation
of pyridine, pyridazine, pyrimidine, pyrazine, s-triazine and 2-deoxy-D-ribose
occurs, concerted bond rearrangement and nuclear motion takes place as op-
posed to stepwise dissociation [papers V and VI].
Publiceringsår
2008
Språk
Engelska
Dokumenttyp
Doktorsavhandling
Förlag
KTH
Ämne
- Electrical Engineering, Electronic Engineering, Information Engineering
Status
Published
Handledare
- Elisabeth Rachlew
ISBN/ISSN/Övrigt
- ISBN: 978-91-7178-852-8
Försvarsdatum
13 mars 2008
Försvarstid
10:15
Försvarsplats
Albanova, Stockholm
Opponent
- Stacey Sorensen