In plasmas and electrolytes the Debye length (also called Debye radius), named after the Dutch physicist and physical chemist Peter Debye, is the measure of a charge carrier's net electrostatic effect in solution, and how far those electrostatic effects persist.
Peter Joseph William Debye {'1': ", '2': ", '3': 'ForMemRS', '4': "} ( ; ] ; March 24, 1884 – November 2, 1966) was a Dutch-American physicist and physical chemist, and Nobel laureate in Chemistry.
The Hückel method or Hückel molecular orbital method (HMO), proposed by Erich Hückel in 1930, is a very simple linear combination of atomic orbitals molecular orbitals (LCAO MO) method for the determination of energies of molecular orbitals of pi electrons in conjugated hydrocarbon systems, such as ethene, benzene and butadiene.
 It is the theoretical basis for the Hückel's rule.
 It was later extended to conjugated molecules such as pyridine, pyrrole and furan that contain atoms other than carbon, known in this context as heteroatoms.
 The extended Hückel method developed by Roald Hoffmann is computational and three-dimensional and was used to test the Woodward–Hoffmann rules.
The Bromley equation was developed in 1973 by Leroy A. Bromley with the objective of calculating activity coefficients for aqueous electrolyte solutions whose concentrations are above the range of validity of the Debye–Hückel equation This equation, together with Specific ion interaction theory (SIT) and Pitzer equations is important for the understanding of the behaviour of ions dissolved in natural waters such as rivers, lakes and sea-water.
In organic chemistry, Hückel's rule estimates whether a planar ring molecule will have aromatic properties.
 The quantum mechanical basis for its formulation was first worked out by physical chemist Erich Hückel in 1931.
 The succinct expression as the 4"n" + 2 rule has been attributed to von Doering (1951), although several authors were using this form at around the same time.
Pitzer equations are important for the understanding of the behaviour of ions dissolved in natural waters such as rivers, lakes and sea-water.
 They were first described by physical chemist Kenneth Pitzer.
 The parameters of the Pitzer equations are linear combinations of parameters, of a virial expansion of the excess Gibbs free energy, which characterise interactions amongst ions and solvent.
 The derivation is thermodynamically rigorous at a given level of expansion.
 The parameters may be derived from various experimental data such as the osmotic coefficient, mixed ion activity coefficients, and salt solubility.
 They can be used to calculate mixed ion activity coefficients and water activities in solutions of high ionic strength for which the Debye–Hückel theory is no longer adequate.
 They are more rigorous than the equations of specific ion interaction theory (SIT theory), but Pitzer parameters are more difficult to determine experimentally than SIT parameters.
Erich Armand Arthur Joseph Hückel {'1': ", '2': ", '3': 'ForMemRS', '4': "} (August 9, 1896, Berlin – February 16, 1980, Marburg) was a German physicist and physical chemist.
 He is known for two major contributions:
The Davies equation is an empirical extension of Debye–Hückel theory which can be used to calculate activity coefficients of electrolyte solutions at relatively high concentrations at 25 °C.
 The equation, originally published in 1938, was refined by fitting to experimental data.
 The final form of the equation gives the mean molal activity coefficient formula_1 of an electrolyte that dissociates into ions having charges "z" and "z" as a function of ionic strength "I":
The chemists Peter Debye and Erich Hückel noticed that solutions that contain ionic solutes do not behave ideally even at very low concentrations.
 So, while the concentration of the solutes is fundamental to the calculation of the dynamics of a solution, they theorized that an extra factor that they termed gamma is necessary to the calculation of the activity coefficients of the solution.
 Hence they developed the Debye–Hückel equation and Debye–Hückel limiting law.
 The activity is only proportional to the concentration and is altered by a factor known as the activity coefficient formula_1.
 This factor takes into account the interaction energy of ions in the solution.
The Debye–Hückel theory was proposed by Peter Debye and Erich Hückel as a theoretical explanation for departures from ideality in solutions of electrolytes and plasmas.
 It is a linearized Poisson–Boltzmann model, which assumes an extremely simplified model of electrolyte solution but nevertheless gave accurate predictions of mean activity coefficients for ions in dilute solution.
 The Debye–Hückel equation provides a starting point for modern treatments of non-ideality of electrolyte solutions.

Question: What Dutch-American physicist and physical chemist, developed the Debye–Hückel equation and Debye–Hückel limiting law with chemist Erich Hückel?
Answer: Peter Debye