src/IntRank2/IntCSA.cc
/* The interaction constants is a scaling factor which is used to express all
   irreducible rank 2 interactions in a consistent fashion (class IntRank2)
   In fact, the interaction constant is maintained in the base class IntRank2
   as member variable _XI in radians/sec. This class simply relates the value
   of _XI to commonly used values that scale shift anisotropy interactions.

   Shift anisotropy interaction constants are returned in units of radian/sec.
   That presents a bit of a problem since these interactions are maintained in
   units of PPM.  The relationship is

                1/2                    1/2                 1/2
     SA   [6*pi]                 [6*pi]              [8*pi]          ^
   xi   = |----| gamma*B *del  = |----| Omega*del  = |----| Omega * / \ sigma
          [ 5  ]        o    zz  [ 5  ]          zz  [ 15 ]         --- 

   where gamma is the spin gyromagnetic ratio, B an applied field strength and
   Omega a spin Larmor frequency.  To obtain the interaction constant in 
   angular frequency units we must convert using the Larmor frequency of the
   spin involved in the interaction. 
 
           Input                SA	: Shift anisotropy interaction
	  			IsoI	: Spin isotope type
	  			Om      : Spin Larmor frequency (Hz)
           Return               xi      : CSA. interaction constant
           Note                           Value is in radians/sec            */
The interaction constants is a scaling factor which is used to express all
irreducible rank 2 interactions in a consistent fashion (class IntRank2)
In fact, the interaction constant is maintained in the base class IntRank2
as member variable _XI in radians/sec. This class simply relates the value
of _XI to commonly used values that scale shift anisotropy interactions.

Shift anisotropy interaction constants are returned in units of radian/sec.
That presents a bit of a problem since these interactions are maintained in
units of PPM.  The relationship is





Input                SA      : Shift anisotropy interaction
IsoI    : Spin isotope type
Om      : Spin Larmor frequency (Hz)
Return               xi      : CSA. interaction constant
Note                           Value is in radians/sec
The interaction constants is a scaling factor which is used to express all irreducible rank 2 interactions in a consistent fashion ( class IntRank2 ) In fact the interaction constant is maintained in the base class IntRank2 as member variable _XI in radians / sec . This class simply relates the value of _XI to commonly used values that scale shift anisotropy interactions . Shift anisotropy interaction constants are returned in units of radian / sec . That presents a bit of a problem since these interactions are maintained in units of PPM . The relationship is Input SA : Shift anisotropy interaction IsoI : Spin isotope type Om : Spin Larmor frequency ( Hz ) Return xi : CSA . interaction constant Note Value is in radians / sec
double IntCSA::xiOm(const string& IsoI, double Om) const
  { 
  Isotope I(IsoI);				
  Isotope H("1H");				
  double IOm = Om*I.gamma()/H.gamma();		
  return xiOm(IOm);				
  }
double IntCSA :: xiOm ( const string & IsoI , double Om ) const { Isotope I ( IsoI ) ; Isotope H ( " " ) ; double IOm = Om * I . gamma ( ) / H . gamma ( ) ; return xiOm ( IOm ) ; }
The interaction constants is a scaling factor which is used to express all
irreducible rank 2 interactions in a consistent fashion (class IntRank2)
In fact, the interaction constant is maintained in the base class IntRank2
as member variable _XI in radians/sec.
The interaction constants is a scaling factor which is used to express all irreducible rank 2 interactions in a consistent fashion ( class IntRank2 ) In fact the interaction constant is maintained in the base class IntRank2 as member variable _XI in radians / sec .
// Construct isotope for IsoI // This is a proton // Larmor frequency I spins // Use overloaded function