NMR Spectroscopy Basics

A technique that utilizes the interaction of atomic nuclei with a magnetic field to study the structure and properties of molecules.

The quantum number that describes the intrinsic angular momentum (or spin) of an electron or nucleus.

Nuclei exhibiting a non-zero nuclear spin, thus capable of interacting with a magnetic field in NMR spectroscopy.

Nuclei with different spin states occupy different energy levels when exposed to a magnetic field.

Electromagnetic radiation used in NMR to induce transitions between nuclear spin energy levels.

Process by which a nucleus returns to its lower energy spin state by transferring energy to the surrounding lattice (sample environment).

Process whereby energy is transferred between nuclei with different spin states.

Characteristic time for spin-lattice relaxation—the average time a nucleus remains in its higher energy state.

The process where nuclei in different spin states, close together, exchange energy, shortening the excited state's lifetime.

Measures the rate at which spin-spin interactions lead to energy loss and a decrease in the net magnetization.

NMR method where the magnetic field strength (B1) or (B0) is scanned to identify the frequencies at which nuclei absorb energy.

The specific frequency at which a nucleus absorbs energy in a magnetic field.

NMR technique that uses the Fourier transform mathematical method to derive spectra from signals measured after applying pulses.

An RF electromagnetic pulse used to tip nuclear spins out of alignment with the static magnetic field.

The signal measured during relaxation after an RF pulse excitation, showing a decaying oscillation.

Constant that dictates the relationship between the magnetic moment of a nucleus and its angular momentum.

Prior to an RF pulse, nuclear spins mostly align with the external magnetic field.

The difference in resonance frequencies (and thus positions in the spectrum) of nuclei in a molecule due to their local environments.

The interaction between the nuclear spins of neighboring atoms that results in splitting of NMR signals.

A unit for expressing chemical shifts, obtained by dividing the measured frequency by the strength of the magnetic field (B0) and multiplying by 10^6.

A reference compound used in NMR spectroscopy to establish zero chemical shift (0 ppm).

Predicting the number of peaks in an NMR spectrum by adding one to the number of equivalent nearby hydrogens.

Nuclear Magnetic Resonance spectroscopy using a magnetic field strength of 60 megahertz.

Nuclear Magnetic Resonance Spectroscopy with a 300-megahertz magnetic field.

A more complicated signal in NMR, resulting from a sample with multiple types of nuclei.

A more intricate pattern of peaks in the NMR spectrum, often showing multiple peaks from different environments of nuclei in the sample.

A series of radio waves in a specific order, used to trigger and measure nuclear signals in NMR

The duration of the radio wave pulse in a NMR experiment.

The time during which the FID (free induction decay) signal is recorded and measured in NMR.

The time the sample needs to return to its original state to measure the next NMR signal.

The specific frequency at which a nucleus in a magnetic field absorbs energy in NMR.

A constant for a given nucleus indicating how strongly it interacts with a magnetic field in NMR.

The strength of the magnetic field used in NMR to interact with the nuclei of the sample.

A spectrum representing the absorption of hydrogen nuclei within a molecule, obtained using NMR.

A reference compound with all its hydrogens in the same environment, used to set a zero frequency in NMR.

The surrounding atoms and bonds that affect the local magnetic field experienced by a nucleus, influencing its NMR absorption.

A group of closely spaced peaks in the NMR spectrum. These indicate multiple nuclei in similar but not identical environments

Small differences in the actual magnetic field strength between NMR instruments with the same nominal value.

A measure of the interaction strength between the spins of nearby atomic nuclei, giving rise to splitting of NMR peaks.

Interaction among neighboring atomic nuclei's magnetic moments, affecting the appearance of NMR signals.

A technique used to remove spin-spin coupling effects, simplifying the spectrum.

The strength of coupling between nuclei decreases as the distance between them increases.

Accurate splitting prediction requires a significant difference between the chemical shift of interacting nuclei and their coupling constant.

NMR method using pulses and mathematical processing to produce spectra from signals.

Using RF pulses to excite nuclei causing to generate a signal.

Replacing protons with deuterium in solvents to eliminate proton signals affecting spectra analysis.

Utilizing superconducting coils to create larger magnetic fields, enabling higher resolution and sensitivity.

The unwanted alteration of the NMR spectrum's peak locations, potentially affecting data accuracy.

An electronic component that transforms analog signals (like NMR signals) into digital form.

Nuclear Magnetic Resonance instruments operating at frequencies in the megaHertz range.

A common NMR frequency range of 10 parts per million for hydrogen measurements.

In a 400 MHz NMR, the useful frequency range is from 400.000 MHz to 400.004 MHz.

Determining the area under NMR peaks to quantify sample components.

Specific NMR technique focusing on hydrogen atom nuclei in molecules.

Using NMR spectra to identify and characterize types of molecules in a sample.

Provides the relative amounts of components in the sample.

A known quantity of a compound used to calibrate NMR measurements for quantification.