Ab Initio Density Functional Theory Calculation: Americium Hydrolysis Mechanism.

Area of Science:

• Nuclear Chemistry
• Theoretical Chemistry
• Materials Science

Background:

• Americium (Am) is a critical actinide element with complex chemical properties.
• Understanding americium's interaction with water (hydrolysis) is vital for nuclear waste management and fuel reprocessing.
• Previous studies have lacked detailed microscopic insights into the americium hydrolysis mechanism.

Purpose of the Study:

• To elucidate the detailed microscopic reaction mechanism of americium hydrolysis.
• To investigate the electronic structure changes and bonding evolution during the reaction.
• To provide theoretical data supporting experimental studies on americium systems.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Microscopic reaction pathways and transition states were analyzed.
• Electronic structure, including orbital interactions and electron transfer, was examined.

Main Results:

• The hydrolysis reaction proceeds along an octet state pathway, yielding americium oxides and hydrogen gas (H2).
• The reaction was determined to be exothermic, releasing energy.
• The interaction between americium and oxygen atoms evolves from electrostatic to increasingly covalent.
• Americium atoms consistently lose electrons, with significant involvement of the 5f orbital and df orbital hybridization.

Conclusions:

• The calculated mechanism provides a detailed understanding of americium hydrolysis at the atomic level.
• The findings highlight the dynamic changes in bonding and electronic structure during the reaction.
• This theoretical work offers crucial data for future experimental investigations of actinides.