SymmetricTensor¶

class mrsimulator.spin_system.tensors.SymmetricTensor(*, name: str = None, description: str = None, label: str = None, property_units: Dict = {'Cq': 'Hz', 'D': 'Hz', 'alpha': 'rad', 'beta': 'rad', 'gamma': 'rad', 'zeta': 'ppm'}, zeta: float = None, Cq: float = None, D: float = None, eta: ConstrainedFloatValue = None, alpha: float = None, beta: float = None, gamma: float = None)¶

Bases: Parseable

Base SymmetricTensor class representing the traceless symmetric part of an irreducible second-rank tensor.

zeta¶

The anisotropy parameter of the nuclear shielding tensor, in ppm, expressed using the Haeberlen convention. The default value is None.

Example

>>> shielding = SymmetricTensor()
>>> shielding.zeta = 10

Type:: float (optional).

Cq¶

The quadrupolar coupling constant, in Hz, derived from the electric field gradient tensor. The default value is None.

Example

>>> efg = SymmetricTensor()
>>> efg.Cq = 10e6

Type:: float (optional).

eta¶

The asymmetry parameter of the SymmetricTensor expressed using the Haeberlen convention. The default value is None.

Example

>>> shielding.eta = 0.1
>>> efg.eta = 0.5

Type:: float (optional).

alpha¶

Euler angle, \(\alpha\), in radians. The default value is None.

Example

>>> shielding.alpha = 0.15
>>> efg.alpha = 1.5

Type:: float (optional).

beta¶

Euler angle, \(\beta\), in radians. The default value is None.

Example

>>> shielding.beta = 3.1415
>>> efg.beta = 1.1451

Type:: float (optional).

gamma¶

Euler angle, \(\gamma\), in radians. The default value is None.

Example

>>> shielding.gamma = 2.1
>>> efg.gamma = 0

Type:: float (optional).

Example

>>> shielding = SymmetricTensor(zeta=10, eta=0.1, alpha=0.15, beta=3.14, gamma=2.1)
>>> efg = SymmetricTensor(Cq=10e6, eta=0.5, alpha=1.5, beta=1.1451, gamma=0)

json(exclude={}, units=True) → dict¶

Parse the class object to a JSON compliant python dictionary object.

Parameters:

exclude – Set of keys that will be excluded from the result.
units – If true, the attribute value is a physical quantity expressed as a string with a number and a unit, else a float.

Returns: dict

classmethod parse_dict_with_units(json_dict: dict)¶

Parse the physical quantity from a dictionary representation of the class object, where the physical quantity is expressed as a string with a number and a unit.

Parameters:: json_dict (dict) – A required python dict object.

reduced_dict(exclude={}) → dict¶

Returns a reduced dictionary representation of the class object by removing all key-value pair corresponding to keys listed in the exclude argument, and keys with value as None.

Parameters:: exclude – A list of keys to exclude from the dictionary.

Return: A dict.

rotate(euler_angles: list) → None¶

Rotate the tensor by the given list of Euler angle rotations. Euler angles are given as a list of (alpha, beta, gamma) tuples, and rotations happen in the Haeberlen (ZYZ) convention.

Parameters:: euler_angles ((list)) – An ordered list of angle tuples (alpha, beta, gamma) to rotate through.

Example

>>> tensor = SymmetricTensor(zeta=10, eta=0.3, alpha=1, beta=1, gamma=1)
>>> angles = [(3.1415, 0, -3.1415), (1.5701, 1.5701, 1.5701)]
>>> tensor.rotate(angles)