Oscar Grånäs
YOU?
Author Swipe
View article: How quantum selection rules influence the magneto-optical effects of driven ultrafast magnetization dynamics
How quantum selection rules influence the magneto-optical effects of driven ultrafast magnetization dynamics Open
Ultrafast magnetization dynamics driven by ultrashort pump lasers is typically explained by changes in the electronic populations and scattering pathways of excited conduction electrons. This conventional approach overlooks the fundamental…
View article: Femtosecond charge and spin dynamics in a Co50Pt50 alloy
Femtosecond charge and spin dynamics in a Co50Pt50 alloy Open
The use of advanced x-ray sources plays a key role in the study of dynamic processes in magnetically ordered materials. The progress in x-ray free-electron lasers enables the direct and simultaneous observation of the femtosecond evolution…
View article: How quantum selection rules influence the magneto-optical effects of driven, ultrafast magnetization dynamics
How quantum selection rules influence the magneto-optical effects of driven, ultrafast magnetization dynamics Open
Ultrafast magnetization dynamics driven by ultrashort pump lasers is typically explained by changes in electronic populations and scattering pathways of excited conduction electrons. This conventional approach overlooks the fundamental rol…
View article: Unlocking atom-specific radiotherapy – DNA backbone breakage caused by X-ray photoactivation
Unlocking atom-specific radiotherapy – DNA backbone breakage caused by X-ray photoactivation Open
The effectiveness of radiation therapy can be enhanced by understanding the fragmentation mechanisms of iodine-doped DNA oligonucleotide under tender X-rays, as explored experimentally and computationally in our study.
View article: Non-equilibrium THz-phonon spin coupling in CrI3
Non-equilibrium THz-phonon spin coupling in CrI3 Open
Manipulating magnetism at the THz timescale in atomically thin ferromagnets by exploiting the interactions of spins with optical phonon modes presents an innovative idea for THz spintronics and magnonics. Utilizing the coupling of phonon m…
View article: Photo-induced Manipulation and Relaxation Dynamics of Weyl-semimetals
Photo-induced Manipulation and Relaxation Dynamics of Weyl-semimetals Open
The use of ultrashort laser pulses to manipulate properties or investigate a materials response on femtosecond time-scales enables detailed tracking of charge, spin and lattice degrees of freedom. When pushing the limits of experimental re…
View article: Element-specific ultrafast lattice dynamics in FePt nanoparticles
Element-specific ultrafast lattice dynamics in FePt nanoparticles Open
Light–matter interaction at the nanoscale in magnetic alloys and heterostructures is a topic of intense research in view of potential applications in high-density magnetic recording. While the element-specific dynamics of electron spins is…
View article: Theoretical Studies of Anisotropic Melting of Ice Induced by Ultrafast Nonthermal Heating
Theoretical Studies of Anisotropic Melting of Ice Induced by Ultrafast Nonthermal Heating Open
Water and ice are routinely studied with X-rays to reveal their diverse structures and anomalous properties. We employ a hybrid collisional-radiative/molecular-dynamics method to explore how femtosecond X-ray pulses interact with hexagonal…
View article: Heat and Work in Quantum Thermodynamics: a Cybernetic Approach
Heat and Work in Quantum Thermodynamics: a Cybernetic Approach Open
We present a new proposal for distinguishing heat from work based on a control-theoretic observability decomposition. We derive a Hermitian operator representing instantaneous dissipation of observable energy, and suggest a generalization …
View article: Heavy element incorporation in nitroimidazole radiosensitizers: molecular-level insights into fragmentation dynamics
Heavy element incorporation in nitroimidazole radiosensitizers: molecular-level insights into fragmentation dynamics Open
The present study investigates the photofragmentation behavior of iodine-enhanced nitroimidazole-based radiosensitizer model compounds in their protonated form using near-edge X-ray absorption mass spectrometry and quantum mechanical calcu…
View article: Photo-induced modification and relaxation dynamics of Weyl-semimetals
Photo-induced modification and relaxation dynamics of Weyl-semimetals Open
The use of ultrashort laser pulses to investigate the response of materials on femtosecond time-scales enables detailed tracking of charge, spin and lattice degrees of freedom. When pushing the limits of the experimental resolution, connec…
View article: Nonequilibrium Phonon Dynamics and Its Impact on the Thermal Conductivity of the Benchmark Thermoelectric Material SnSe
Nonequilibrium Phonon Dynamics and Its Impact on the Thermal Conductivity of the Benchmark Thermoelectric Material SnSe Open
Thermoelectric materials play a vital role in the pursuit of a sustainable energy system by allowing the conversion of waste heat to electric energy. Low thermal conductivity is essential to achieving high-efficiency conversion. The conduc…
View article: The interplay of local electron correlations and ultrafast spin dynamics in fcc Ni
The interplay of local electron correlations and ultrafast spin dynamics in fcc Ni Open
The complex electronic structure of metallic ferromagnets is determined by a balance between exchange interaction, electron hopping leading to band formation, and local Coulomb repulsion. The interplay between the respective terms of the H…
View article: Extended Lagrangian Born-Oppenheimer Molecular Dynamics with DFT+U
Extended Lagrangian Born-Oppenheimer Molecular Dynamics with DFT+U Open
Extended Lagrangian Born-Oppenheimer molecular dynamics (XL-BOMD) [Phys. Rev. Lett. vol. 100, 123004 (2008)] is combined with Kohn-Sham density functional theory (DFT) using a DFT+U correction based on the Hubbard model. This combined XL-B…
View article: Influence of strain on an ultrafast phase transition
Influence of strain on an ultrafast phase transition Open
The flexibility of 2D materials combined with properties highly sensitive to strain makes strain engineering a promising avenue for manipulation of both structure and function.
View article: Influence of deuterium-induced volume changes on optical transmission in Fe/V (001) and Cr/V (001) superlattices
Influence of deuterium-induced volume changes on optical transmission in Fe/V (001) and Cr/V (001) superlattices Open
The deuterium-induced changes of the optical transmission in Fe/V (001) and Cr/V (001) superlattices are found experimentally to be dominated by the volume changes of the vanadium layers and thus indirectly linked to concentration. The deu…
View article: Photo-induced Hidden Phase of 1T-TaS2 with Tunable Lifetime
Photo-induced Hidden Phase of 1T-TaS2 with Tunable Lifetime Open
Phase transitions are ubiquitous, appearing at every length scale from atoms to galaxies. In condensed matter, ultrafast laser pulses drive materials to highly non-equilibrium conditions allowing transitions to new phases of matter not att…
View article: Element-selective ultrafast magnetization dynamics of hybrid Stoner-Heisenberg magnets
Element-selective ultrafast magnetization dynamics of hybrid Stoner-Heisenberg magnets Open
Stoner and Heisenberg excitations in magnetic materials are inherently\ndifferent. The former involves an effective reduction of the exchange\nsplitting, whereas the latter comprises excitation of spin-waves. In this work,\nwe test the imp…
View article: X-ray Induced Fragmentation of Protonated Cystine
X-ray Induced Fragmentation of Protonated Cystine Open
We demonstrate site-specific X-ray induced fragmentation across the sulfur L-edge of protonated cystine, the dimer of the amino acid cysteine. Ion yield NEXAFS were performed in the gas phase using electrospray ionization (ESI) in combinat…
View article: X-ray induced fragmentation of protonated cystine
X-ray induced fragmentation of protonated cystine Open
We demonstrate site-specific X-ray induced fragmentation across the sulfur L-edge of protonated cystine, the dimer of the amino acid cysteine. Ion yield NEXAFS were performed in the gas phase using electrospray ionization (ESI) in combinat…
View article: Ultrafast manipulation of the NiO antiferromagnetic order <i>via</i> sub-gap optical excitation
Ultrafast manipulation of the NiO antiferromagnetic order <i>via</i> sub-gap optical excitation Open
We present a comprehensive investigation of ultrafast demagnetisation and accompanying band gap reduction in a charge transfer insulator using time-resolved resonant X-ray reflectivity.
View article: Imaging of femtosecond bond breaking and charge dynamics in ultracharged peptides
Imaging of femtosecond bond breaking and charge dynamics in ultracharged peptides Open
We study bond breaking and charge dynamics of ionized peptides in both real and reciprocal space.
View article: <i>In Situ</i> Pseudopotentials for Electronic Structure Theory
<i>In Situ</i> Pseudopotentials for Electronic Structure Theory Open
We present a general method of constructing in situ pseodopotentials from first-principles, all-electron, and full-potential electronic structure calculations of a solid. The method is applied to bcc Na, at low-temperature equilibrium volu…
View article: Manipulation of Stacking Order in <i>Td</i>-WTe<sub>2</sub> by Ultrafast Optical Excitation
Manipulation of Stacking Order in <i>Td</i>-WTe<sub>2</sub> by Ultrafast Optical Excitation Open
Subtle changes in stacking order of layered transition metal dichalcogenides may have profound influence on the electronic and optical properties. The intriguing electronic properties of Td-WTe2 can be traced to the break of inversion symm…
View article: Orientation before destruction. A multiscale molecular dynamics study
Orientation before destruction. A multiscale molecular dynamics study Open
The emergence of ultra-fast X-ray free-electron lasers opens the possibility of imaging single molecules in the gas phase at atomic resolution. The main disadvantage of this imaging technique is the unknown orientation of the sample expose…
View article: Reproducibility in the unfolding process of protein induced by an external electric field
Reproducibility in the unfolding process of protein induced by an external electric field Open
The dynamics of proteins are crucial for their function. However, commonly used techniques for studying protein structures are limited in monitoring time-resolved dynamics at high resolution. Combining electric fields with existing techniq…
View article: Reproducibility in the unfolding process of protein induced by an external electric field
Reproducibility in the unfolding process of protein induced by an external electric field Open
Controlled unfolding of proteins can reveal structural properties and give insights of the proteins' dynamics. We show the feasibility of unfolding proteins in the gas phase using electric fields, with a well-defined path at high field str…
View article: A Perspective on Molecular Structure and Bond-Breaking in Radiation Damage in Serial Femtosecond Crystallography
A Perspective on Molecular Structure and Bond-Breaking in Radiation Damage in Serial Femtosecond Crystallography Open
X-ray free-electron lasers (XFELs) have a unique capability for time-resolved studies of protein dynamics and conformational changes on femto- and pico-second time scales. The extreme intensity of X-ray pulses can potentially cause signifi…