circular dichroism: meaning, definition, pronunciation and examples
Rare / SpecialistFormal / Technical
Quick answer
What does “circular dichroism” mean?
The difference in absorption of left- and right-handed circularly polarized light by a material.
Audio
Pronunciation
Definition
Meaning and Definition
The difference in absorption of left- and right-handed circularly polarized light by a material.
A spectroscopic technique used to study the structural asymmetry (chirality) of molecules, particularly the secondary structure of proteins and the conformation of nucleic acids.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Pronunciation differences follow standard British-American vowel patterns. Spelling is identical.
Connotations
None beyond its strict technical definition.
Frequency
Equally rare and specialized in both dialects, confined to relevant scientific literature and discussion.
Grammar
How to Use “circular dichroism” in a Sentence
The [PROTEIN] exhibits strong circular dichroism at 222 nm.Circular dichroism of the [SAMPLE] was measured.The structure was determined by circular dichroism.Vocabulary
Collocations
Examples
Examples of “circular dichroism” in a Sentence
verb
British English
- The sample was circularly dichroic, so we planned to dichroise it further. (Note: 'dichroise' is extremely rare and technical).
American English
- The complex dichroises strongly in the visible region. (Note: verb forms are highly atypical).
adverb
British English
- The light was circularly dichroically absorbed. (Grammatical but exceedingly awkward; not used).
American English
- The sample reacted circular-dichroistically. (Not used).
adjective
British English
- The circular dichroism spectrometer was recently calibrated.
- They obtained circular-dichroism spectra.
American English
- The circular dichroism signal was positive.
- Circular dichroism measurements indicated a helical structure.
Usage
Meaning in Context
Business
Not used.
Academic
Primary context. Used in research papers, theses, and seminars in chemistry, biochemistry, biophysics, and pharmaceutical sciences.
Everyday
Never used.
Technical
Defining context. Refers to both a physical phenomenon and a standard laboratory analytical technique.
Vocabulary
Synonyms of “circular dichroism”
Strong
Neutral
Weak
Vocabulary
Antonyms of “circular dichroism”
Watch out
Common Mistakes When Using “circular dichroism”
- Using it as a countable noun (e.g., 'two circular dichroisms').
- Confusing it with 'fluorescence' or 'absorbance' spectroscopy.
- Misspelling as 'circular dikroism' or 'circular dichronism'.
FAQ
Frequently Asked Questions
Its primary application is determining the secondary structure (e.g., alpha-helix, beta-sheet) of proteins and the conformational states of nucleic acids like DNA and RNA.
No, they are related chiroptical phenomena but different. Optical rotation measures the rotation of plane-polarized light, while circular dichroism measures the differential absorption of left- and right-handed circularly polarized light, providing more detailed structural information.
No, it provides low-resolution structural information about the overall content of secondary structure elements (percentages of helix, sheet, etc.) but cannot determine the full atomic-resolution tertiary structure like X-ray crystallography or NMR can.
It is a plot of the difference in molar absorptivity (Δε) for left- and right-circularly polarized light (y-axis) against wavelength (x-axis). Characteristic shapes and peaks correlate with specific structural motifs.
The difference in absorption of left- and right-handed circularly polarized light by a material.
Circular dichroism is usually formal / technical in register.
Circular dichroism: in British English it is pronounced /ˈsɜːkjʊlə daɪˈkrəʊɪzəm/, and in American English it is pronounced /ˈsɜːrkjələr daɪˈkroʊɪzəm/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “none”
Learning
Memory Aids
Mnemonic
Imagine a circular (spiral) staircase. Two people (light beams) of opposite handedness try to climb it. One fits perfectly, the other doesn't—this difference in 'absorption' is the core idea.
Conceptual Metaphor
A tool that 'sees' the twist and fold of molecules, much like polarized sunglasses see stress patterns in plastic.
Practice
Quiz
Circular dichroism is primarily used to analyse what property of molecules?