qiskit.chemistry.algorithms.pes_samplers.MorsePotential

class MorsePotential(molecule)

Implements a 1D Morse potential.

Input units are Angstroms (distance between the two atoms), and output units are Hartrees (molecular energy).

Initializes the potential to the zero-function. fit() should be used afterwards to fit the potential to computed molecular energies.

매개변수

molecule (Molecule) – the underlying molecule.

예외

ValueError – Only implemented for diatomic molecules

__init__(molecule)

Initializes the potential to the zero-function. fit() should be used afterwards to fit the potential to computed molecular energies.

매개변수

molecule (Molecule) – the underlying molecule.

예외

ValueError – Only implemented for diatomic molecules

Methods

__init__(molecule)	Initializes the potential to the zero-function.
dissociation_energy([scaling])	Returns the calculated dissociation energy for the current fit.
eval(x)	After fitting the data to the fit function, predict the energy at a point x.
fit(xdata, ydata[, initial_vals, bounds_list])	Fits a potential to computed molecular energies.
fit_function(x, d_e, alpha, r_0, m_shift)	Functional form of the potential.
fundamental_frequency()	Returns the fundamental frequency for the current fit (in s^-1).
get_equilibrium_geometry([scaling])	Returns the interatomic distance corresponding to minimal energy.
get_maximum_trusted_level([n])	Returns the maximum energy level for which the particular implementation still provides a good approximation of reality.
get_minimal_energy([scaling])	Returns the smallest molecular energy for the current fit.
get_num_modes()	This (1D) potential represents a single vibrational mode
get_trust_region()	The potential will usually be well-defined (even if not useful) for arbitrary x so we return a fairly large interval here.
update_molecule(molecule)	Updates the underlying molecule.
vibrational_energy_level(n)	Returns the n-th vibrational energy level for the current fit (in Hartrees).
wave_number()	Returns the wave number for the current fit (in cm^-1).

dissociation_energy(scaling=1.0)

Returns the calculated dissociation energy for the current fit.

매개변수

scaling (float) – Scaling to change units. (Default is 1.0 for Hartrees)

반환 형식

float

반환값

calculated dissociation energy for the current fit

eval(x)

After fitting the data to the fit function, predict the energy at a point x.

매개변수

x (float) – value to evaluate surface in

반환 형식

float

반환값

value of surface in point x

fit(xdata, ydata, initial_vals=None, bounds_list=None)

Fits a potential to computed molecular energies.

매개변수

• xdata (List[float]) – interatomic distance points (Angstroms)

• ydata (List[float]) – molecular energies (Hartrees)

• initial_vals (Optional[List[float]]) – Initial values for fit parameters. None for default. Order of parameters is d_e, alpha, r_0 and m_shift (see fit_function implementation)

• bounds_list (Optional[Tuple[List[float], List[float]]]) – Bounds for the fit parameters. None for default. Order of parameters is d_e, alpha, r_0 and m_shift (see fit_function implementation)

반환 형식

None

static fit_function(x, d_e, alpha, r_0, m_shift)

Functional form of the potential.

매개변수

• x (float) – x parameter of morse potential

• d_e (float) – d_e parameter of morse potential

• alpha (float) – alpha parameter of morse potential

• r_0 (float) – r_0 parameter of morse potential

• m_shift (float) – m_shift parameter of morse potential

반환 형식

float

반환값

potential functional form

fundamental_frequency()

Returns the fundamental frequency for the current fit (in s^-1).

반환 형식

float

반환값

fundamental frequency for the current fit

get_equilibrium_geometry(scaling=1.0)

Returns the interatomic distance corresponding to minimal energy.

매개변수

scaling (float) – Scaling to change units. (Default is 1.0 for Angstroms)

반환 형식

float

반환값

interatomic distance corresponding to minimal energy

get_maximum_trusted_level(n=0)

Returns the maximum energy level for which the particular implementation still provides a good approximation of reality.

매개변수

n (int) – vibronic mode

반환 형식

float

반환값

maximum_trusted_level estimated

get_minimal_energy(scaling=1.0)

Returns the smallest molecular energy for the current fit.

매개변수

scaling (float) – Scaling to change units. (Default is 1.0 for Hartrees)

반환 형식

float

반환값

smallest molecular energy for the current fit

get_num_modes()

This (1D) potential represents a single vibrational mode

반환 형식

int

get_trust_region()

The potential will usually be well-defined (even if not useful) for arbitrary x so we return a fairly large interval here. Redefine in derived classes if needed.

반환 형식

Tuple[float, float]

update_molecule(molecule)

Updates the underlying molecule.

매개변수

molecule (Molecule) – chemistry molecule

예외

ValueError – Only implemented for diatomic molecules

반환 형식

None

vibrational_energy_level(n)

Returns the n-th vibrational energy level for the current fit (in Hartrees).

매개변수

n (int) – vibrational mode

반환 형식

float

반환값

vibrational energy level for the current fit

wave_number()

Returns the wave number for the current fit (in cm^-1).

반환 형식

float

반환값

wave number for the current fit