H in H2O

 h(h2o)    LANL       EVAL-apr93 MACFARLANE                       
 ref. 4 (1994)        DIST-MAY10                       20100309   
----JENDL-4.0         MATERIAL 1                                  
-----THERMAL NEUTRON SCATTERING DATA                              
------ENDF-6 FORMAT                                               
 The data were taken from ENDF/B-VI.8.                            
 temperatures = 296 350 400 450 500 600 800 1000 deg k.           
 this evaluation was generated at the los alamos national         
 laboratory (april 93) using the leapr code.  the physical        
 model is very similar to the one used at general atomic          
 in 1969 to produced the original endf/b-iii evaluations          
 (see ref. 1).  the alpha and beta grids were extended, and       
 the constants were changed to match the endf/b-vi values.        
 water is represented by freely recoiling h2o molecules of        
 mass 18.  each molecule can undergo torsional harmonic           
 oscillations (hindered rotations) with a broad spectrum of       
 distributed modes.  between 0.04 and 0.165 ev, the rotation      
 spectrum is taken from the work of haywood and thorson (ref. 2)  
 joined to a quadratic law below 0.04 ev.  In addition, there     
 are two internal vibrations at frequencies of 0.205 and 0.48 ev  
 taken over from the Nelkin model (ref. 3) with slightly          
 readjusted masses of 6 and 3, respectively.  the torsional band  
 is normalized to a mass of 18/8.  the scattering by the          
 oxygen atoms is not included in the tabulated scattering         
 law data.  it should be taken into account by adding the         
 the scattering for free oxygen of mass 16.                       
 1. j.u.koppel and d.h.houston, reference manual for endf thermal 
    neutron scattering data, general atomic report ga-8774        
    revised and reissued as endf-269 by the national nuclear      
    data center, july 1978.                                       
 2. b.c.haywood and j.m.thorson, "proc. conf. on neutron          
    thermalization", brookhaven (1962).                           
 3. m.s.nelkin, phys. rev. 119, 741(1960).                        
 4. r.e.macfarlane, new thermal neutron scattering files for      
    endf/b-vi release 2, los alamos national laboratory report    
    LA-12639-MS (ENDF-356) March 1994.