nuclear isomer
C2Technical/Scientific
Definition
Meaning
An excited, metastable state of an atomic nucleus that has a different energy level and longer lifetime than the ground state of the same nucleus.
In nuclear physics and chemistry, a nuclear species that shares the same atomic number and mass number as another but exists in a quantum state with different internal energy and properties. The isomer has a measurably long half-life before decaying to a more stable state.
Linguistics
Semantic Notes
A nuclear isomer is not a different element or isotope; it is a different energetic configuration of the *same* nucleus. The term 'isomer' here is analogous to, but distinct from, its use in chemistry for molecules.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Spelling follows regional conventions for other words in a sentence (e.g., 'behaviour' vs. 'behavior').
Connotations
Purely technical, identical in both dialects.
Frequency
Exclusively used in nuclear physics, radiochemistry, and related academic/technical fields. Frequency is extremely low in general discourse.
Vocabulary
Collocations
Grammar
Valency Patterns
The [isotope] exists as a nuclear isomer.Researchers observed the [decay/gamma rays] from the nuclear isomer.The [excitation] leads to the formation of a nuclear isomer.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “None applicable.”
Usage
Context Usage
Business
Virtually never used.
Academic
Central term in nuclear physics research papers, theses, and advanced textbooks.
Everyday
Never used.
Technical
Used in nuclear engineering, medical physics (e.g., in discussions of technetium-99m for imaging), and astrophysics (nucleosynthesis).
Examples
By Part of Speech
verb
British English
- The nucleus can isomerise under specific conditions.
- The beam is used to isomerise the target material.
American English
- The nucleus can isomerize under specific conditions.
- The beam is used to isomerize the target material.
adverb
British English
- The state decayed isomerically.
- The nucleus was isomerically purified.
American English
- The state decayed isomerically.
- The nucleus was isomerically purified.
adjective
British English
- The isomerisation process was carefully modelled.
- They measured the isomeric transition.
American English
- The isomerization process was carefully modeled.
- They measured the isomeric transition.
Examples
By CEFR Level
- Some medical scans use a special type of radioactive material called a nuclear isomer.
- Scientists talk about nuclear isomers when an atom's core has extra energy for a long time.
- The metastable nuclear isomer Technetium-99m is vital in diagnostic nuclear medicine due to its ideal half-life.
- Research focused on populating the high-spin nuclear isomer to study its unique decay pathway.
Learning
Memory Aids
Mnemonic
Think of an 'isomer' in chemistry as a different shape of the same molecule; a 'nuclear isomer' is a different 'energy shape' of the same nucleus.
Conceptual Metaphor
A wound-up spring inside the nucleus; it's the same object but stores extra energy that it only releases slowly over time.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Direct translation 'ядерный изомер' is accurate. Trap: confusing it with 'изотоп' (isotope), which is a different nucleus altogether.
Common Mistakes
- Mispronouncing 'isomer' as 'iso-mer' (should be 'eye-so-mer').
- Confusing it with a chemical isomer.
- Using it as a synonym for 'isotope'.
Practice
Quiz
What defines a nuclear isomer?
FAQ
Frequently Asked Questions
No. An isotope has a different number of neutrons. A nuclear isomer is the exact same isotope (same protons, same neutrons) but in an excited, longer-lived energy state.
Yes. Technetium-99m (the 'm' stands for metastable) is a nuclear isomer of Technetium-99. It is used in tens of millions of medical diagnostic procedures annually.
Lifetimes vary enormously, from nanoseconds to years or even longer. Some isomers have half-lives of minutes or hours, which makes them useful in applications like medicine.
It helps us understand nuclear structure, stellar nucleosynthesis (how elements are made in stars), and enables practical technologies like nuclear batteries and advanced medical imaging.