Electron interactions with the heteronuclear carbonyl precursor H2FeRu3(CO)13 and comparison with HFeCo3(CO)12: from fundamental gas phase and surface science studies to focused electron beam induced deposition

In the current contribution we present a comprehensive study on the heteronuclear carbonyl complex H2FeRu3(CO)13 covering its low energy electron induced fragmentation in the gas phase through dissociative electron attachment (DEA) and dissociative ionization (DI), its decomposition when adsorbed on a surface under controlled ultrahigh vacuum (UHV) conditions and exposed to irradiation with 500 eV electrons, and its performance in focused electron beam induced deposition (FEBID) at room temperature under HV conditions. The performance of this precursor in FEBID is poor, resulting in maximum metal content of 26 atom % under optimized conditions. Furthermore, the Ru/Fe ratio in the FEBID deposit (≈3.5) is higher than the 3:1 ratio predicted. This is somewhat surprising as in recent FEBID studies on a structurally similar bimetallic precursor, HFeCo3(CO)12, metal contents of about 80 atom % is achievable on a routine basis and the deposits are found to maintain the initial Co/Fe ratio. Low temperature (≈213 K) surface science studies on thin films of H2FeRu3(CO)13 demonstrate that electron stimulated decomposition leads to significant CO desorption (average of 8–9 CO groups per molecule) to form partially decarbonylated intermediates. However, once formed these intermediates are largely unaffected by either further electron irradiation or annealing to room temperature, with a predicted metal content similar to what is observed in FEBID. Furthermore, gas phase experiments indicate formation of Fe(CO)4 from H2FeRu3(CO)13 upon low energy electron interaction. This fragment could desorb at room temperature under high vacuum conditions, which may explain the slight increase in the Ru/Fe ratio of deposits in FEBID. With the combination of gas phase experiments, surface science studies and actual FEBID experiments, we can offer new insights into the low energy electron induced decomposition of this precursor and how this is reflected in the relatively poor performance of H2FeRu3(CO)13 as compared to the structurally similar HFeCo3(CO)12.The authors acknowledge the fruitful and productive environment provided by the COST Action CELINA CM1301 and we would like to take the opportunity to extend our thanks to Prof. Petra Swiderek for running this Action exceptionally well. Marc Hanefeld and Michael Huth acknowledge financial support by the Deutsche Forschungsgemeinschaft (DFG) through Priority Program SPP 1928, project HU 752/12-1. DHF thanks the National Science Foundation for support of this work through the linked collaborative grants CHE-1607621 and CHE-1607547. OI acknowledges supported from the Icelandic Center of Research (RANNIS) Grant No. 13049305(1-3) and the University of Iceland Research Fund. RKTP acknowledges a doctoral grant from the University of Iceland Research Fund and financial support from the COST Action CM1301; CELINA, for short term scientific missions (STSMs).Peer Reviewe

2D-REMPI of HBr: Study of singlet and triplet Rydberg states and the ion-pair state

Fjölljóseindajónun og truflana flugtíma-litrófsgreiningar voru framkvæmdar fyrir tveggja ljóseinda gleypni á HBr á sviðinu 78960 – 79820 cm-1 til að mæla litróf f3Δ1 (1,0), F1Δ2 (1,0), V1Σ+ (m+7) og H1Σ+ (0,0) orkuástandanna. Nýjar gleypnilínur sjást í fyrsta skipti innan f3Δ1 (1,0), F1Δ2 (1,0) og V1Σ+ (m+7) ástandanna. Truflanaáhrifa á milli F1Δ2 (1,0) og V1Σ+ (m+7) eru gerð skil og tilsvarandi truflanareikningar eru framkvæmdir. Sömuleiðis sjást truflanaáhrif á milli H1Σ+ (0,0) ástandsins og V1Σ+ (m+7) og V1Σ+ (m+8) ástandanna, og tilsvarandi truflanareikningar H1Σ+ (0,0) ástandsins framkvæmdir. Línufærslu-greining, jónpara hlutfalls-greining og glæný bandvíddar-greining eru framkvæmdar til staðfestingar á truflanaáhrifum á milli F og V ástandanna annars vegar og H og V ástandanna hins vegar. Staðsetning atómlína er svo loks hagnýtt til útskýringa á frávikum sem eiga sér stað í ákvörðun nýrra gleypnilína og línufærslu-greiningum.Two-photon resonance enhanced multi-photon ionization time-of-flight (REMPI-TOF) analysis was performed for HBr in the region 78960 – 79820 cm-1 to obtain 1D REMPI spectra of the f3Δ1, F1Δ2, V1Σ+ and H1Σ+ states. New line positions are assigned for the f3Δ1, F1Δ2 and V1Σ+ states for the first time. Near-resonance interaction effects are observed and calculated for interactions between the F1Δ2 and V1Σ+ (m+7) states. Perturbation effects are also observed and calculated for interactions between the H1Σ+ state and the V (m+7) and V (m+8) states. Line shift analysis, ion-pair signal intensity ratio analysis (IPSIRA), and last but not least a state-of-the-art bandwidth analysis is successfully performed to confirm near-resonance interaction between the F and V state and perturbation effects between the H and V states. Atomic line positions are finally applied to explain various deviations in assignment and line shift

State interactions, excitation dynamics, hidden states and photofragmentation pathways in hydrogen halides

The focus of my Ph.D. work is on two separate, but closely related experimental subjects. The first involves the recording of mass resolved two-photon resonance enhanced multiphoton ionization (REMPI) spectra of the hydrogen halides HBr and HI. The REMPI spectra of both molecules reveal extensive perturbation effects; line-shifts, intensity alterations, and line broadenings. These are colloquially referred to as LS-, LI-, and LW-effects, respectively. Measuring these effects quantitatively and qualitatively allows data extraction regarding state interactions (perturbations) between Rydberg and ion-pair states. These interactions include fragmentation via repulsive valence states and subsequent ionization of the fragments. The presence of hidden states is also deduced and they are assigned based on observed perturbation effects. Velocity map imaging (VMI) experiments are performed on HBr. Such experiments measure the angular distributions of photofragmentations and the total kinetic energy release of the imaged fragments. These experiments allow the roles of photofragment channels in the photodissociation and photoionization to be deduced, where Rydberg and ion-pair states act as intermediary states prior to ionization/fragmentation.Þungamiðja doktorsverkefnis míns snerist um tvö aðskilin en náskyld viðfangsefni. Hið fyrra snýst um mælingar á samhrifsstyrktum fjölljóseindajónunar (REMPI) rófum vetnihalíðanna HBr og HI. Skráð róf beggja sameinda leiddu í ljós umtalsverð truflunaráhrif; línuhliðranir, breytingar á línustyrkjum og línuvíkkanir. Þessi áhrif eru til styttingar kölluð LS-, LI- og LW-áhrif. Að mæla þessi áhrif hlutbundið og eigindlega gerir gagnasöfnun varðandi víxlverkanir á milli Rydberg og jónparaástanda mögulega. Þessar víxlverkanir fela m.a. í sér ljóssundrun í gegnum fráhrindandi ástönd og jónun atómbrotanna sem úr þeim myndast. Dulin ástönd eru sömuleiðis fundin í gegnum truflanaáhrif. Hraðavigurskortlagningar (VMI) eru framkvæmdar á HBr. Slíkar tilraunir mæla stefnu og hreyfiorku jónaðra atómbrota. Með niðurstöðum þessara tilrauna má finna hvaða ljósbrotsferlar koma við sögu í ljósrofnunar- og jónunarferlum sameindarinnar þar sem Rydberg og jónparaástönd taka þátt sem miðbiksástönd