Erratum: Publisher's Note: "Laser-induced electron diffraction of the ultrafast umbrella motion in ammonia" [Struct. Dyn. 8, 014301 (2021)].

[This corrects the article DOI: 10.1063/4.0000046.].

Laser-induced electron diffraction of the ultrafast umbrella motion in ammonia.

Visualizing molecular transformations in real-time requires a structural retrieval method with Ångström spatial and femtosecond temporal atomic resolution. Imaging of hydrogen-containing molecules additionally requires an imaging method sensitive to the atomic positions of hydrogen nuclei, with most methods possessing relatively low sensitivity to hydrogen scattering. Laser-induced electron diffraction (LIED) is a table-top technique that can image ultrafast structural changes of gas-phase polyatomic molecules with sub-Ångström and femtosecond spatiotemporal resolution together with relatively high sensitivity to hydrogen scattering. Here, we image the umbrella motion of an isolated ammonia molecule (NH3) following its strong-field ionization. Upon ionization of a neutral ammonia molecule, the ammonia cation (NH3 +) undergoes an ultrafast geometrical transformation from a pyramidal ( Φ HNH = 107 ° ) to planar ( Φ HNH = 120 ° ) structure in approximately 8 femtoseconds. Using LIED, we retrieve a near-planar ( Φ HNH = 117 ± 5 ° ) field-dressed NH3 + molecular structure 7.8 - 9.8 femtoseconds after ionization. Our measured field-dressed NH3 + structure is in excellent agreement with our calculated equilibrium field-dressed structure using quantum chemical ab initio calculations.

Molecular structure retrieval directly from laboratory-frame photoelectron spectra in laser-induced electron diffraction.

Ubiquitous to most molecular scattering methods is the challenge to retrieve bond distance and angle from the scattering signals since this requires convergence of pattern matching algorithms or fitting methods. This problem is typically exacerbated when imaging larger molecules or for dynamic systems with little a priori knowledge. Here, we employ laser-induced electron diffraction (LIED) which is a powerful means to determine the precise atomic configuration of an isolated gas-phase molecule with picometre spatial and attosecond temporal precision. We introduce a simple molecular retrieval method, which is based only on the identification of critical points in the oscillating molecular interference scattering signal that is extracted directly from the laboratory-frame photoelectron spectrum. The method is compared with a Fourier-based retrieval method, and we show that both methods correctly retrieve the asymmetrically stretched and bent field-dressed configuration of the asymmetric top molecule carbonyl sulfide (OCS), which is confirmed by our quantum-classical calculations.

Table-top high-energy 7 µm OPCPA and 260 mJ Ho:YLF pump laser.

We present a state-of-the-art compact high-energy mid-infrared (mid-IR) laser system for TW-level eight-cycle pulses at 7 µm. This system consists of an Er:Tm:Ho:fiber MOPA which serves as the seeder for a ZGP-based optical parametric chirped pulse amplification (OPCPA) chain, in addition to a Ho:YLF amplifier which is Tm:fiber pumped. Featuring all-optical synchronization, the system delivers 260 mJ pump energy at 2052 nm and 16 ps duration at 100 Hz with a stability of 0.8% rms over 20 min. We show that chirp inversion in the OPCPA chain leads to excellent energy extraction and aids in compression of the 7 µm pulses to eight optical cycles (188 fs) in bulk BaF2 with 93.5% efficiency. Using 21.7 mJ of the available pump energy, we generate 0.75 mJ energy pulses at 7 µm due to increased efficiency with a chirp inversion scheme. The pulse quality of the system's output is shown by generating high harmonics in ZnSe which span up to harmonic order 13 with excellent contrast. The combination of the passive carrier-envelope phase stable mid-IR seed pulses and the high-energy 2052 nm picosecond pulses makes this compact system a key enabling tool for the next generation of studies on extreme photonics, strong field physics, and table-top coherent X-ray science.

Towards integration of a liquid-filled fiber capillary for supercontinuum generation in the 1.2-2.4 µm range.

We demonstrate supercontinuum generation in unspliced as well as in integrated CS(2)-filled capillary fibers at different pump wavelengths of 1030 nm, 1510 nm, and 1685 nm. A novel method for splicing a liquid-filled capillary fiber to a standard single-mode optical fiber is presented. This method is based on mechanical splicing using a direct-laser written polymer ferrule using a femtosecond two-photon polymerization process. We maintain mostly single-mode operation despite the multi-mode capability of the liquid-filled capillaries. The generated supercontinua exhibit a spectral width of over 1200 nm and 1000 nm for core diameters of 5 µm and 10 µm, respectively. This is an increase of more than 50 percent compared to previously reported values in the literature due to improved dispersion properties of the capillaries.

Mid-infrared Fourier-transform spectroscopy with a high-brilliance tunable laser source: investigating sample areas down to 5 µm diameter.

We demonstrate highly sensitive infrared spectroscopy of sample volumes close to the diffraction limit by coupling a femtosecond fiber-feedback optical parametric oscillator (OPO) to a conventional Fourier-transform infrared (FTIR) spectrometer. The high brilliance and long-term stable infrared radiation with 1e(2)-bandwidths up to 125 nm is easily tunable between 1.4 µm and 4.2 µm at 43 MHz repetition rate and thus enables rapid and low-noise infrared spectroscopy. We demonstrate this by measuring typical molecular vibrations in the range of 3 µm. Combined with surface-enhanced infrared spectroscopy, where the confined electromagnetic near-fields of resonantly excited metal nanoparticles are employed to enhance molecular vibrations, we realize the spectroscopic detection of a molecular monolayer of octadecanethiol. In comparison to conventional light sources and synchrotron radiation, our compact table-top OPO system features a significantly improved performance making it highly suitable for rapid analysis of minute amounts of molecular species in life science and medicine laboratories.

GRAND: the German retrospective cohort analysis on compliance and persistence and the associated risk of fractures in osteoporotic women treated with oral bisphosphonates.

UNLABELLED: This database analysis of over 4,000 German women prescribed oral bisphosphonates between December 2004 and November 2007 showed that compliance and persistence with oral bisphosphonates in German women with osteoporosis were inadequate. INTRODUCTION: GRAND is a database analysis designed to investigate persistence and compliance with oral bisphosphonate regimens, and their association with fracture incidence, in women with osteoporosis. METHODS: Diagnostic, treatment and fracture data were obtained from the IMS Disease Analyzer patient database in Germany. Women with osteoporosis prescribed one of six specified oral bisphosphonates between December 2004 and November 2007 with no similar prescription for at least 1 year beforehand were eligible for analysis. Those treated with intravenous bisphosphonates were excluded. Persistence (prescription refill gap of ≤ 30 days or change of treatment frequency) and compliance (medication possession ratio) were measured for 2 years from therapy start. RESULTS: Data from 4,147 women were evaluable, with a median oral bisphosphonate treatment duration of 145.5 days. Persistence rates after 1 and 2 years were 27.9% and 12.9%, respectively, and 66.3% of women were compliant. As expected, persistence rates were higher when the refill gap was increased to 60 or 90 days. No significant differences in 1-year persistence between patients on weekly or monthly treatment regimens were observed (28.6% and 29.4%, respectively), although 1-year persistence with daily treatment was only 7.2%. After 24 months of therapy, compliant women had fewer fractures than non-compliant women (88.1% and 85.0% fracture-free, respectively; p = 0.0147). In multivariate Cox regression analysis, treatment compliance was the only factor that significantly decreased fracture risk (p = 0.0034). CONCLUSIONS: Compliance and persistence with oral bisphosphonates in German women with osteoporosis were inadequate. Better compliance and persistence can prevent fractures in these women.

[Pegfilgrastim vs filgrastim in primary prophylaxis of febrile neutropenia in patients with breast cancer after chemotherapy: a cost-effectiveness analysis for Germany]. / Pegfilgrastim vs. Filgrastim zur Primärprophylaxe der febrilen Neutropenie bei Brustkrebspatientinnen nach Chemotherapie: Eine Kosten-Effektivitäts-Analyse für Deutschland.

OBJECTIVE: Febrile neutropenia (FN) is a common toxic side effect of myelosuppressive chemotherapy. The cost-effectiveness of primary prophylaxis (PP) of FN with granulocyte colony stimulating growth factor (G-CSF) filgrastim for six or eleven days was compared to single dose pegfilgrastim in patients with early breast cancer receiving chemotherapy (>or= 20 % FN risk) as simulated in a model. METHODS: Based on a decision-analytical model we conducted a cost-effectiveness analysis (CEA) and a cost-utility analysis (CUA) from the perspective of the Statutory Health Insurance (SHI) in Germany. The model simulated three clinical alternatives being built on each other, that pegfilgrastim and filgrastim had differential impact on (1) the risk of FN, (2) on FN-related mortality, and (3) on the achieved chemotherapy relative dose intensity (RDI) leading to gain in long-term survival. RESULTS: Assuming a 5.5 % lower risk of FN for PP with pegfilgrastim than an 11-day course of filgrastim provided - from the perspective of the SHI - a cost saving of Euro 2,229. A gain of 0.039 quality-adjusted life-years (QALY) resulted when the third alternative was used. Assuming a 10.5 % lower risk of FN for PP with pegfilgrastim than a 6-day filgrastim course, the third alternative showed an incremental cost-effectiveness ratio (ICER) of Euro 17.165 per life-year gained (LYG) and Euro 18.324 per QALY with 0.074 QALYs gained. CONCLUSION: These results indicate that PP with pegfilgrastim is cost saving compared to 11-day use of filgrastim and cost-effective compared to 6-day use of filgrastim in patients with breast cancer treated in Germany.