Source Code for Module lib.nmr

 1  ############################################################################### 
 2  #                                                                             # 
 3  # Copyright (C) 2013 Edward d'Auvergne                                        # 
 4  #                                                                             # 
 5  # This file is part of the program relax (http://www.nmr-relax.com).          # 
 6  #                                                                             # 
 7  # This program is free software: you can redistribute it and/or modify        # 
 8  # it under the terms of the GNU General Public License as published by        # 
 9  # the Free Software Foundation, either version 3 of the License, or           # 
10  # (at your option) any later version.                                         # 
11  #                                                                             # 
12  # This program is distributed in the hope that it will be useful,             # 
13  # but WITHOUT ANY WARRANTY; without even the implied warranty of              # 
14  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               # 
15  # GNU General Public License for more details.                                # 
16  #                                                                             # 
17  # You should have received a copy of the GNU General Public License           # 
18  # along with this program.  If not, see <http://www.gnu.org/licenses/>.       # 
19  #                                                                             # 
20  ############################################################################### 
21   
22  # Module docstring. 
23  """Module containing functions related to basic NMR concepts.""" 
24   
25  # Python module imports. 
26  from math import pi 
27   
28  # relax module imports. 
29  from lib.physical_constants import g1H, return_gyromagnetic_ratio 
30   
31   
32 -def frequency_to_Hz(frq=None, B0=None, isotope=None): 
33      """Convert the given frequency from ppm to Hertz units. 
34   
35      @keyword frq:       The frequency in ppm. 
36      @type frq:          float 
37      @keyword B0:        The magnetic field strength as the proton frequency in Hertz. 
38      @type B0:           float 
39      @keyword isotope:   The isotope type of the nucleus of interest. 
40      @type isotope:      str 
41      @return:            The frequency in Hertz. 
42      @rtype:             float 
43      """ 
44   
45      # Convert and return. 
46      return frq * B0 / g1H * return_gyromagnetic_ratio(isotope) * 1e-6 
47   
48   
49 -def frequency_to_ppm(frq=None, B0=None, isotope=None): 
50      """Convert the given frequency from Hertz to ppm units. 
51   
52      @keyword frq:       The frequency in Hertz. 
53      @type frq:          float 
54      @keyword B0:        The magnetic field strength as the proton frequency in Hertz. 
55      @type B0:           float 
56      @keyword isotope:   The isotope type of the nucleus of interest. 
57      @type isotope:      str 
58      @return:            The frequency in ppm. 
59      @rtype:             float 
60      """ 
61   
62      # Convert and return. 
63      return frq / B0 * g1H / return_gyromagnetic_ratio(isotope) / 1e-6 
64   
65   
66 -def frequency_to_rad_per_s(frq=None, B0=None, isotope=None): 
67      """Convert the given frequency from ppm to rad/s units. 
68   
69      @keyword frq:       The frequency in ppm. 
70      @type frq:          float 
71      @keyword B0:        The magnetic field strength as the proton frequency in Hertz. 
72      @type B0:           float 
73      @keyword isotope:   The isotope type of the nucleus of interest. 
74      @type isotope:      str 
75      @return:            The frequency in rad/s. 
76      @rtype:             float 
77      """ 
78   
79      # Convert and return. 
80      return frq * 2.0 * pi * B0 / g1H * return_gyromagnetic_ratio(isotope) * 1e-6 
81