Advanced Scattering Phase Shifts Calculator

Analyze partial-wave scattering with flexible physics inputs. Switch methods, inspect outputs, and compare energy trends. Export clean reports, tables, and charts for study today.

Calculator Inputs

Large screens show 3 columns, smaller screens show 2, and mobile shows 1.

Plotly Graph

The chart compares phase shift and total partial cross section across the selected energy range.

Example Data Table

These rows are illustrative sample scenarios for checking the interface and output style.

Method Energy (MeV) l Key inputs Approx. phase shift Use case
Hard-sphere 5.0 0 a = 3.5 fm, μ = 469.5 MeV/c² Moderate positive shift Simple elastic reference model
Effective-range 2.0 0 as = 5.2 fm, re = 1.8 fm Large low-energy s-wave shift Threshold behavior study
Direct S-matrix 8.0 1 Sl = 0.54 + 0.72i Complex elastic and reaction output Inelasticity inspection
Coefficients 6.0 2 A = 1.0, B = 0.25 Small positive phase Wave matching exercises

Formulas Used

1) Wave number

The calculator first converts energy into a wave number using

k = √(2μE) / ħc

2) Hard-sphere model

For an impenetrable sphere, the boundary condition gives

tan(δl) = jl(ka) / nl(ka)

3) Effective-range expansion

Near threshold, the s-wave obeys

k cot(δ0) = -1/as + (rek²)/2

4) Direct S-matrix relation

If Sl = ηe2iδl, then

δl = ½ arg(Sl) and η = |Sl|

5) Partial cross sections

For elastic channels, the calculator uses

σl = (4π/k²)(2l+1) sin²(δl)

For direct S-matrix input, the elastic and reaction contributions are separated using η.

How to Use This Calculator

  1. Choose a phase-shift method that matches your model or data source.
  2. Enter the incident energy, reduced mass, and orbital angular momentum.
  3. Fill in the method-specific fields such as radius, effective-range terms, S-matrix values, or asymptotic coefficients.
  4. Set the graph energy range and the number of plot points.
  5. Press Calculate phase shift to place the results above the form.
  6. Inspect δ, k, η, cross sections, resonance notes, and the plotted energy trend.
  7. Use the CSV and PDF buttons to export the current summary.

FAQs

1) What is a scattering phase shift?

A scattering phase shift measures how an interaction changes the phase of an outgoing partial wave relative to free motion. It is a compact way to describe elastic scattering dynamics at each angular momentum.

2) Why does the calculator need reduced mass?

The reduced mass sets the momentum scale for two-body scattering. It appears in the wave-number relation and therefore affects the phase shift, cross sections, and the energy trend shown in the graph.

3) When should I use the hard-sphere model?

Use the hard-sphere option when you want a simple elastic benchmark with an excluded radius. It is useful for intuition, testing, and rough comparisons against more realistic interaction models.

4) What does the effective-range option represent?

It approximates low-energy s-wave scattering with the scattering length and effective range. This is especially helpful near threshold, where detailed potential information is often replaced by compact parameters.

5) Why can the S-matrix method show reaction cross section?

When |Sl| is below 1, part of the incoming flux leaves the elastic channel. The calculator interprets that loss through η and reports a reaction contribution alongside the elastic partial cross section.

6) What does a phase near 90° mean?

A phase shift near 90° can suggest resonance-like behavior, especially when it changes rapidly with energy. The calculator adds a resonance note, but you should still confirm the interpretation with a fuller physical model.

7) Why does the coefficient method use tan(δ) = B/A?

That convention matches a common asymptotic wave decomposition where coefficient ratios encode the phase offset. If your source uses a different sign or normalization, transform the coefficients before entering them.

8) Are the outputs exact for all scattering problems?

No. The results are only as accurate as the selected model and your inputs. The tool is designed for study, estimation, and structured comparisons rather than replacing a full numerical scattering solver.

Related Calculators

black hole temperature

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.