TY  - JOUR
A1  - Eckert, Sebastian
A1  - Vaz da Cruz, Vinicius
A1  - Ertan, Emelie
A1  - Ignatova, Nina
A1  - Polyutov, Sergey
A1  - Couto, Rafael C.
A1  - Fondell, Mattis
A1  - Dantz, Marcus
A1  - Kennedy, Brian
A1  - Schmitt, Thorsten
A1  - Pietzsch, Annette
A1  - Odelius, Michael
A1  - Föhlisch, Alexander
T1  - One-dimensional cuts through multidimensional potential-energy surfaces by tunable x rays
JF  - Physical review : A, Atomic, molecular, and optical physics
N2  - The concept of the potential-energy surface (PES) and directional reaction coordinates is the backbone of our description of chemical reaction mechanisms. Although the eigenenergies of the nuclear Hamiltonian uniquely link a PES to its spectrum, this information is in general experimentally inaccessible in large polyatomic systems. This is due to (near) degenerate rovibrational levels across the parameter space of all degrees of freedom, which effectively forms a pseudospectrum given by the centers of gravity of groups of close-lying vibrational levels. We show here that resonant inelastic x-ray scattering (RIXS) constitutes an ideal probe for revealing one-dimensional cuts through the ground-state PES of molecular systems, even far away from the equilibrium geometry, where the independent-mode picture is broken. We strictly link the center of gravity of close-lying vibrational peaks in RIXS to a pseudospectrum which is shown to coincide with the eigenvalues of an effective one-dimensional Hamiltonian along the propagation coordinate of the core-excited wave packet. This concept, combined with directional and site selectivity of the core-excited states, allows us to experimentally extract cuts through the ground-state PES along three complementary directions for the showcase H2O molecule.
Y1  - 2018
U6  - https://doi.org/10.1103/PhysRevA.97.053410
SN  - 2469-9926
SN  - 2469-9934
VL  - 97
IS  - 5
PB  - American Physical Society
CY  - College Park
ER  -