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IMSL_CONSTANT

IMSL_CONSTANT

IMSL_CONSTANT

The IMSL_CONSTANT function returns the value of various mathematical and physical constants.

The names allowed are listed in the table that follows. Values marked with (mp) are exact (to machine precision). The references in the right-hand column are indicated by code numbers: (1) for Cohen and Taylor (1986), (2) for Liepman (1964), and (3) for precomputed mathematical constants. The supported units are listed below.

Name

Description

Value

Ref.

amu

atomic mass unit

1.6605655 x 10–27 kg

1

ATM

standard atm. pressure

1.01325 x 105 N/m2 (mp)

2

AU

astronomical unit

1.496 x 1011 m

 

Avogadro

Avogadro’s number, N

6.022045 x 1023 1/mole

1

Boltzman

Boltzman’s constant, k

1.380662 x 10–23 J / K

1

C

speed of light, c

2.997924580 x 108 m/s

1

Catalan

Catalan’s constant

0.915965... (mp)

3

E

base of natural logs, e

2.718... (mp)

3

ElectronCharge

electron charge, e

1.6021892 x 10–19 C

1

ElectronMass

electron mass, me

9.109534 x 10–31 kg

1

ElectronVolt

electron volt, ev

1.6021892 x 10–19 J

1

Euler

Euler’s constant, γ

0.577... (mp)

3

Faraday

Faraday constant, F

9.648456 x 104 C/mole

1

FineStructure

fine structure, α

7.2973506 x 10–3

1

Gamma

Euler’s constant, γ

0.577... (mp)

3

Gas

gas constant, R0

8.31441 J/mole/K

1

Gravity

gravitational constant, G

6.6720 x 10–11 N m2 / kg2

1

Hbar

Planck’s constant / 2π

1.0545887 x 10–34 J s

1

PerfectGasVolume

std. vol. ideal gas

2.241383 x 10–2 m3 / mole

1

Pi

Pi, π

3.141... (mp)

3

Planck

Planck’s constant, h

6.626176 x 10–34 J s

1

ProtonMass

proton mass, Mp

1.6726485 x 10–27 kg

1

Rydberg

Rydberg’s constant, Rinfinity

1.097373177 x 107 /m

1

Speedlight

speed of light, c

2.997924580 x 108 m/s

1

StandardGravity

standard g

9.80665 m/s2 (mp)

2

StandardPressure

standard atm. pressure

1.01325 x 105 N/m2 (mp)

2

StefanBoltzman

Stefan-Boltzman, σ

5.67032 x 10–8 W/K4 /m2

1

WaterTriple

triple point of water

2.7316 x 102 K

2

The units allowed are as follows:

Unit

Description

time

day, hour = hr, min = minute, s = sec = second, year

frequency

Hertz = Hz

mass

AMU, g = gram, lb = pound, ounce = oz, slug

distance

Angstrom, AU, feet = foot, in = inch, m = meter = metre, micron, mile, mill, parsec, yard

area

acre

volume

l = liter = litre

force

dyne, N = Newton

energy

BTU, Erg, J = Joule

work

W = watt

pressure

ATM = atmosphere, bar

temperature

degC = Celsius, degF = Fahrenheit, degK = Kelvin

viscosity

poise, stoke

charge

Abcoulomb, C = Coulomb, statcoulomb

current

A = ampere, abampere, statampere

voltage

Abvolt, V = volt

magnetic induction

T = Tesla, Wb = Weber

other units

l, farad, mole, Gauss, Henry, Maxwell, Ohm

The metric prefixes listed in the next table can be used with the previous units. The one- or two-letter prefixes can only be used with one-letter unit abbreviations.

     
Prefix Definition Value
a atto 10–18
f femto 10–15
p pico 10–12
n nano 10–9
u micro 10–6
m milli 10–3
c centi 10–2
d deci 10–1
dk deca 102
k kilo 103
  myria 104
  mega 106
g giga 109
t tera 1012

There is no one-letter unit abbreviation for myria or mega since m means milli.



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