Atom Class¶

The atom class contains useful reference numbers for a given atomic species, like mass, nuclear \(g\)-factor, with states and transitions useful for laser cooling. Data comes from Daniel Steck’s “Alkali D-line data”, Tobias Tiecke’s “Properties of Potassium” and Michael Gehm’s “Properties of 6Li”.

Overview¶

atom(species)

A class containing reference data for select laser-coolable alkali atoms

Detailed functions¶

class pylcp.atom(species)[source]¶

A class containing reference data for select laser-coolable alkali atoms

Parameters: species (string) – The isotope number and species of alkali atom. For lithium-7, species can be eiter “7Li” or “Li7”, for example. Supported species are “6Li”, “7Li”, “23Na”, “39K”, “40K”, “41K”, “85Rb”, “87Rb”, and “133Cs”.

I¶

Nuclear spin of the isoptope

Type: float

gI¶

Nuclear g-factor of the isotope. Note that the nuclear g-factor is specified relative to the Bohr magneton, not the nuclear magneton.

Type: float

mass¶

Mass, in kg, of the atom.

Type: float

states¶

States of the atom useful for laser cooling, in order of increasing energy.

Type: list of pylcp.atom.state

transitions¶

Transitions in the atom useful for laser cooling. All transitions are from the ground state.

Type: list of pylcp.atom.transition

class pylcp.atom.state(n=None, S=None, L=None, J=None, lam=None, E=None, tau=inf, gJ=1, Ahfs=0, Bhfs=0, Chfs=0)[source]¶

The quantum state and its parameters for an atom.

Parameters

n (integer) – Principal quantum number of the state.
S (integer or float) – Total spin angular momentum of the state.
L (integer or float) – Total orbital angular momentum of the state.
J (integer or float) – Total electronic angular momentum of the state.
lam (float, optional) – Wavelength, in meters, of the photon necessary to excite the state from the ground state. electronic angular momentum of the state.
E (float, optional) – Energy of the state above the ground state in \(\text{cm}^{-1}\).
tau (float, optioanl) – Lifetime of the state in s. If not specified, it is assumed to be infinite (the ground state).
gJ (float) – Total angular momentum Lande g-factor.
Ahfs (float) – A hyperfine coefficient.
Bhfs (float) – B hyperfine coefficient.
Chfs (float) – C hyperfine coefficient.

gamma¶

Lifetime in \(\text{s}^{-1}\)

Type: float

gammaHz¶

Corresponding linewidth in Hz, given by \(\gamma/2\pi\).

Type: float

energy¶

The energy in \(\text{cm}^{-1}\)

Type: float

Notes

All the parameters passed to the class on creation are stored as attrributes, with the exception of lam and E, one of which defines the stored attribute energy. One of these two optional variable must be specified.

This construction of the state assumes L-S coupling.

class pylcp.atom.transition(state1, state2, mass)[source]¶