Units of electric dipole moment in molecular physics Electric dipole moments for molecules are often reported in debye (D). Is it correct to say that electric dipole moment is expressed in the debye unit (noting that SI uses coulomb–metre)?

Introduction / Context:
The electric dipole moment is a fundamental quantity in electromagnetism and spectroscopy, characterizing charge separation in molecules. While SI units employ coulomb–metre (C·m), molecular physics and chemistry commonly use the debye (D) for convenience because typical molecular dipoles are of order a few debye.

Given Data / Assumptions:

• SI base unit: C·m.
• Practical chemistry unit: 1 debye ≈ 3.33564 × 10^-30 C·m.
• Context is reporting/expressing molecular dipoles.

Concept / Approach:

An electric dipole moment p is defined as p = q * d for two equal/opposite charges separated by displacement d. Although SI is the standard for unit consistency, long-standing practice in spectroscopy lists dipole moments in debye. Therefore, saying “dipole moment is expressed in debye unit” is acceptable in molecular contexts, with a known conversion to SI.

Step-by-Step Solution:

Verification / Alternative check:

Handbooks (physical chemistry, spectroscopy) and databases list molecular dipoles (e.g., H2O ≈ 1.85 D) in debye; SI equivalents are readily obtained via the conversion factor.

Why Other Options Are Wrong:

• “False” ignores widespread scientific usage.
• “Only solids/gases” limits are arbitrary.
• Statcoulomb–centimetre is CGS electrostatic; debye is the conventional practical unit.

Common Pitfalls:

Assuming debye is an SI unit; it is not, but is standard in practice. Always provide SI conversions when required.

Final Answer:

True