Imaging of transition charge densities involving carbon core excitations by all X-ray sum-frequency generation.
Philos Trans A Math Phys Eng Sci
; 377(2145): 20170470, 2019 May 20.
Article
in En
| MEDLINE
| ID: mdl-30929629
ABSTRACT
X-ray diffraction signals from the time-evolving molecular charge density induced by selective core excitation of chemically inequivalent carbon atoms are calculated. A narrowband X-ray pulse selectively excites the carbon K-edge of the -CH3 or -CH2F groups in fluoroethane (CH3-CH2F). Each excitation creates a distinct core coherence which depends on the character of the electronic transition. Direct propagation of the reduced single-electron density matrix, using real-time time-dependent density functional theory, provides the time-evolving charge density following interactions with external fields. The interplay between partially filled valence molecular orbitals upon core excitation induces characteristic femtosecond charge migration which depends on the core-valence coherence, and is monitored by the sum-frequency generation diffraction signal. This article is part of the theme issue 'Measurement of ultrafast electronic and structural dynamics with X-rays'.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Quantum Theory
/
X-Ray Diffraction
/
Carbon
Type of study:
Prognostic_studies
Language:
En
Journal:
Philos Trans A Math Phys Eng Sci
Journal subject:
BIOFISICA
/
ENGENHARIA BIOMEDICA
Year:
2019
Type:
Article
Affiliation country:
United States