CCL:G: Electronic potential g09 output

 Sent to CCL by: "Sara  Tortorella" [sara{}chemiome.chm.unipg.it]
 Hi everyone,
 I'm new to this forum (...and also to computational chemistry!), so I'm
 wondering if you could help me in clarifying the electrostatic properties
 section of gaussian 09 output.
 In particular, I'm performing B3LYP/6-31g* Pop=MK or Pop=CHelpG in order to
 obtain an estimation of atomic charges. Below you can see the output I get.
 The question is: how is the electric potential reported below the charges (from
 '1 Atom    -14.652466' to the end) exactly calculated? It is the same I could
 get with the cubegen potential utility (but in different units)? Is it the
 potential the MK or CHelpG charges are trying to fit?
 Any references will be appreciated!
 Fitting point charges to electrostatic potential
  Charges from ESP fit, RMS=   0.00190 RRMS=   0.07922:
  Charge=   0.00000 Dipole=     3.5674    -6.6676    -2.0973 Tot=     7.8474
               1
      1  C   -0.041036
      2  C    0.100413
      3  N    0.080397
      4  C    0.104730
      5  N   -0.419796
      6  C   -0.228373
      7  S   -0.123685
      8  C    0.369090
      9  N   -0.595642
     10  C    0.472394
     11  N   -0.666989
     12  C    0.639533
     13  N   -0.603091
     14  H    0.419839
     15  C    0.259744
     16  N   -0.485481
     17  C    0.047084
     18  N    0.863622
     19  O   -0.420014
     20  O   -0.442699
     21  H    0.137993
     22  H    0.113894
     23  H    0.117979
     24  H    0.094647
     25  H    0.076982
     26  H    0.128461
 -----------------------------------------------------------------
               Electrostatic Properties (Atomic Units)
  -----------------------------------------------------------------
     Center     Electric         -------- Electric Field --------
                Potential          X             Y             Z
  -----------------------------------------------------------------
     1 Atom    -14.652466
     2 Atom    -14.647722
     3 Atom    -18.250028
     4 Atom    -14.649824
     5 Atom    -18.341442
     6 Atom    -14.659441
     7 Atom    -59.145459
     8 Atom    -14.643023
     9 Atom    -18.341917
    10 Atom    -14.653606
    11 Atom    -18.337872
    12 Atom    -14.633363
    13 Atom    -18.255162
    14 Atom     -0.954134
    15 Atom    -14.632556
    16 Atom    -18.337428
    17 Atom    -14.679161
    18 Atom    -18.117945
    19 Atom    -22.308685
    20 Atom    -22.308127
    21 Atom     -1.047777
    22 Atom     -1.070324
    23 Atom     -1.061627
    24 Atom     -1.067950
    25 Atom     -1.092820
    26 Atom     -1.041033
  -----------------------------------------------------------------
 Thank you in advance for your precious help!
 Sara
 sara],[chemiome.chm.unipg.it