Investigation of the molecular and isotopic response to deposition, thermal maturity, hydrocarbon generation, and expulsion : A multidisciplinary approach based on the Cenozoic sequences on Svalbard

Understanding the generation, expulsion and migration of hydrocarbons and the associated effects on the molecular composition of generated products plays a major role in petroleum system analyses. The presented PhD study is based on a research well from the Central Tertiary Basin of Svalbard which has not been investigated in detail previously. The core material from this well is of exceptional quality. A comprehensive depositional reconstruction of the lithologies of the research well has been established by combining inorganic and organic geochemistry. Shedding a light on the effects of sulphate reduction on the preserved organic matter quality supported a better understanding of the depositional settings and natural quality limitations on the present-day organic matter concentration. The effects of thermal maturity on the organic matter and on selected biomarker compounds as well as on molecular maturity proxies has been investigated. The implementation of multivariate statistics has led to the creation of a novel unitless biomarker maturity trend. Molecular fractionation effects associated with the expulsion and migration of hydrocarbons have been investigated. The findings show that polar compounds and asphaltenes were preferentially retained in the organic rich layers of the lower Frysjaodden Fm. On the other hand, the expelled hydrocarbons have migrated upwards and mainly consist of saturated compounds of low polarity. The development of an advanced maturity-based back calculation approach made it possible to calculate the amounts of hydrocarbons that have been generated, expelled and migrated with respect to their initial organic matter quality and quantity. In addition to the geoscientific investigations, two analytical methodologies have been developed in the course of this PhD project. The first methodology involves the multiple detector coupling to a single gas chromatograph in order to enhance the data density per injection and significantly reduce the sample preparation work for organic geochemical analyses. The second method is used to monitor the isotopic composition of the Rock Eval S1 and S2 parameters in an online analysis. This analytical setup was described for the first time. The results support a better understanding of isotopic fractionation effects introduced by thermal maturation and hydrocarbon generation and expulsion. The results from these analyses have also been used to confirm the impact of sulphate reduction on the reactive organic matter proportion in the Paleocene Eocene transition of the investigated well

Streaking temporal double slit interference by an orthogonal two-color laser field

We investigate electron momentum distributions from single ionization of Ar by two orthogonally polarized laser pulses of different color. The two-color scheme is used to experimentally control the interference between electron wave packets released at different times within one laser cycle. This intracycle interference pattern is typically hard to resolve in an experiment. With the two-color control scheme these features become the dominant contribution to the electron momentum distribution. Furthermore the second color can be used for streaking of the otherwise interfering wave packets establishing a which-way marker. Our investigation shows that the visibility of the interference fringes depends on the degree of the which-way information determined by the controllable phase between the two pulses.Comment: submitted to PR

Observation of the Efimov state of the helium trimer

Quantum theory dictates that upon weakening the two-body interaction in a three-body system, an infinite number of three-body bound states of a huge spatial extent emerge just before these three-body states become unbound. Three helium atoms have been predicted to form a molecular system that manifests this peculiarity under natural conditions without artificial tuning of the attraction between particles by an external field. Here we report experimental observation of this long predicted but experimentally elusive Efimov state of $^{4}$He$_{3}$ by means of Coulomb explosion imaging. We show spatial images of an Efimov state, confirming the predicted size and a typical structure where two atoms are close to each other while the third is far away

Investigating absolute stereochemical configuration with coulomb explosion imaging

It is a particularly challenging task in stereochemistry to determine the absolute configuration of chiral molecules, i.e. to assign to a given sample the microscopic enantiomeric structure. In recent years, Coulomb Explosion Imaging (CEI) has been shown to yield directly the absolute configuration of small molecules in the gas phase. This contribution describes the experimental basics of this approach, highlights the most significant results and discusses limitations. A short discussion on extending Coulomb Explosion Imaging beyond analytic aspects to fundamental questions of molecular chirality concludes this review

Chiral photoelectron angular distributions from ionization of achiral atomic and molecular species

We show that the combination of two achiral components - atomic or molecular target plus a circularly polarized photon - can yield chirally structured photoelectron angular distributions. For photoionization of CO, the angular distribution of carbon K-shell photoelectrons is chiral when the molecular axis is neither perpendicular nor (anti-)parallel to the light propagation axis. In photo-double-ionization of He, the distribution of one electron is chiral, if the other electron is oriented like the molecular axis in the former case and if the electrons are distinguishable by their energy. In both scenarios, the circularly polarized photon defines a plane with a sense of rotation and an additional axis is defined by the CO molecule or one electron. This is sufficient to establish an unambiguous coordinate frame of well-defined handedness. To produce a chirally structured electron angular distribution, such a coordinate frame is necessary, but not sufficient. We show that additional electron-electron interaction or scattering processes are needed to create the chiral angular distribution

Kinematically complete experimental study of Compton scattering at helium atoms near the ionization threshold

Compton scattering is one of the fundamental interaction processes of light with matter. Already upon its discovery [1] it was described as a billiard-type collision of a photon kicking a quasi-free electron. With decreasing photon energy, the maximum possible momentum transfer becomes so small that the corresponding energy falls below the binding energy of the electron. Then ionization by Compton scattering becomes an intriguing quantum phenomenon. Here we report a kinematically complete experiment on Compton scattering at helium atoms below that threshold. We determine the momentum correlations of the electron, the recoiling ion, and the scattered photon in a coincidence experiment finding that electrons are not only emitted in the direction of the momentum transfer, but that there is a second peak of ejection to the backward direction. This finding links Compton scattering to processes as ionization by ultrashort optical pulses [2], electron impact ionization [3,4], ion impact ionization [5,6], and neutron scattering [7] where similar momentum patterns occur.Comment: 7 pages, 4 figure

Genetic Survey of Psilocybe Natural Products

Psilocybe magic mushrooms are best known for their main natural product, psilocybin, and its dephosphorylated congener, the psychedelic metabolite psilocin. Beyond tryptamines, the secondary metabolome of these fungi is poorly understood. The genomes of five species ( P. azurescens , P. cubensis , P. cyanescens , P. mexicana , and P. serbica ) were browsed to understand more profoundly common and species‐specific metabolic capacities. The genomic analyses revealed a much greater and yet unexplored metabolic diversity than evident from parallel chemical analyses. P. cyanescens and P. mexicana were identified as aeruginascin producers. Lumichrome and verpacamide A were also detected as Psilocybe metabolites. The observations concerning the potential secondary metabolome of this fungal genus support pharmacological and toxicological efforts to find a rational basis for yet elusive phenomena, such as paralytic effects, attributed to consumption of some magic mushrooms